Bug: Selecting Text Causing Other Lines to Render as Random Characters (in Edge v81.0.403.1)


Since updating to Edge v81.0.403.1 (as well as KB4528760 and KB4532938 at the same time in my case), I (and several others) are often encountering a major text rendering issue where nearly whole lines of text end up completely scrambled with seemingly random symbols appearing in place of letters, with different random symbols occurring ever time re-rendering of the text is triggered.


You can see the issue in the screenshot below of this page on (for example, out of the dozens of sites it's occurred on).

Edge Text Rendering Bug 1.jpg

This issue occurs frequently (up to dozens of times per day), always after selecting text, but not ever time text is selected. This issue has occurred with dozens of different websites, and regardless of whether browsing in InPrivate mode with all extensions disabled.


This issue only began occurring around 1/30/2020 after I updated to Edge Chromium Dev v81.0.403.1 (64-bit) and also installed KB4528760 and KB4532938 for Windows 10 Pro 1909 x64 (18363.592) at the same time, and I haven't encountered with any other browsers or Windows apps or UI.


This often (but not always) affects nearly a whole line (after word-wrap) of text, often (but not always) in the paragraph following the one where text had been selected.


Any action which causes the text to be rendered again – such as Alt-Tab (to a window on top of the browser) and back again, or selecting the affected text (to highlight it), or Win+Shift+S (causing screen to be tinted gray for screenshot selection), etc. – causes different random symbols to appear for the exact same portion of text that was affected.



In some cases, deselecting all text will cause the rendering issues to temporarily cease, and in other cases, it just causes the random symbols to change to different random symbols instead.


This is an intermittent issue. At times I can reproduce it dozens of times in a row, and other times I can go 20 minutes without being able to reproduce it even when trying intentionally to do so. Refreshing a page can cause this issue to go away temporarily. However, once it starts occurring it seems to occur more often for various pages or every time text is selected on a page.


I also reported this issue with steps to reproduce via Send Feedback in Edge Dev, along with my email address. However, as I, unfortunately, have no way to reference that report here or reply to it or know it will be noticed (as can't flag as a bug or critical issue), I'm reporting it here as well. I'd appreciate it if this bug report could be passed along to the development team, especially as others have confirmed this issue here in this forums.


I'm reporting the issue here with further details in case it may prove helpful, and also so that it may be easier for others encountering the same issue to find here so don't have to take the time to write up their own details reports regarding it. After, my initial report, I also found others, such as @josh_bodner@jbart007 and @Heath Bates, in this reply to the Edge v81.0.403.1 release announcement thread.


My Configuration

  • Edge Chromium Dev v81.0.403.1 (64-bit)
  • Windows 10 Pro 1909 x64 (18363.592)
  • KB4528760 and KB4532938 just installed at same time as the Edge Dev update
  • For about:flags, I have Disabled #calculate-native-win-occlusion, #web-contents-occlusion and Enabled #edge-autoplay-user-setting-block-option, #dns-over-https, #quiet-notification-prompts.
  • Multiple Edge Dev instances open with different profiles and 3 screens in use.
  • NVIDIA GeForce GTX 1060 (Driver 441.66 installed 12/10/19)
  • 32GB RAM
  • Intel i9-9900K.
  • Issues only began after updating Edge Dev and Windows, not any adjustment of flags, drivers or other configuration or browser usage changes.


Additional Screenshots of the Issue


As seen in these screenshots, this issue results in different random symbols showing each time re-rendering is triggered for text which occurs in close proximity to where different text had been selected. Sometimes different lines end up affected, sometimes the issue temporarily disappears after deselecting text, and sometimes different symbols appear for the exact same portion of text when triggering re-rendering or when changing what, if any, other text is selected.


Edge Text Rendering Bug 2.jpg


Edge Text Rendering Bug 3 Large.jpg


Edge Text Rendering Bug 4 Combined.png

4 Replies
best response confirmed by Dan Moorehead | PowerAccess (Contributor)
1. the problem is only happening in Edge Dev channel, other channels like stable or Canary don't have that problem.
2. Windows 10 updates don't have effects on it, very unlikely, because I'm on insider fast ring, didn't install those updates that belong to stable Windows 10, yet I could easily reproduce that bug on Edge Dev.
3. best thing is to wait it out, the fix is already included in Canary, so on the next major update, Dev will also receive the bug fixes.

@HotCakeX thanks for the update. I'm glad to hear a fix is in the pipeline for release to Edge Dev channel.

Unfortunately, the major update for Dev channel just out today (81.0.410.1) failed to fix the text rendering issues occurring after text selection.

You can see the issue remains in the below screenshot (eg. occurring at ) with random characters under "Pay as you go" above the selected text, which appears as different random symbols every time re-rendering occurs (eg. Alt-Tab and back):

Also, the issue remains even after deselecting text, as shown in the below screenshot, even after Alt-Tab or otherwise causing it be re-rendered again:


@Dan Moorehead | PowerAccess 


"the visual glitch is completely random and not caused by any user actions, although highlighting the text should fix it (at least until it happens again). It's caused by an upstream Chromium bug, and we received the fix for it from them earlier this week, so it should make it into the next Dev release."