I have noticed on the new Edge that when searching in the Lastpass extension and then wanting to select one of the launch buttons, they move to the top of the selection area. This does not happen on the original Edge, so assuming that they are the same extension (I selected "Lastpass for Microsoft Edge" for each browser) it's the new Edge that isn't rendering it properly?
I can confirm the same behaviour. This started happening about a week ago. Both Edge and Lastpass have recently launched new versions so it's hard to tell where the problem is, but I don't see this bug with the same version of the Lastpass browser extension in Chrome.