I am a long time Excel user. In this moment I have a subscription on Office 365 Home Edition. After a recent update Excel (and also other Office 365 products like MS Word) have a new clipboard feature.
The following problem occurs in my Office 365 instalation when performing a copy-and-past (Ctrl-C/Ctrl-V) of even a single cell to another cell, Excel blocks for a five or more seconds. I appears to me that Excel is trying to make a connection to one of the discs (local or OneDrive), tries to open a file or so. If I click somewhere in the spreadsheet then the whole screen will be grayed-out and in the caption of the Excel Window appears the text "não responde" until Excel has finished what it started to do (I use Excel in Portuguese language, but translated in English "não response" should be something like "doesn't answer"). This anomaly behaviour happens only during the first copy-and-past command. Subsequent copy-and-past commands work "normal". I use an up-to-date PC with an I7 processor and 32 GB Ram. This PC has an SSD to start up Windows 10 Pro (V 1809). Office 365 Home Ed. is installed onto this SSD. I tried the Copy-and-paste feature in Excel during a "safe" mode session (via Win+R -> Excel /safe<Enter>. Even in this "safe" session this very annoying delay occurred. Note: my local copy of OneDrive is installed on a second harddisk (not the boot SSD where Office is installed).