I have several spreadsheets with ActiveX CommandButton objects that I used to invoke my macros. These all worked fine up until a few days ago (~ 13 Jan 2019) when strange issues started to occur.
The buttons will now only respond intermittently to clicks, and sometimes not at all. If they do start to respond, it is only briefly and then they stop responding again. The weird thing is that the buttons do continue to respond correctly and consistently
to the associated accelerator keys.
In addition, the buttons are now not being painted correctly. The 3 strange looking rectangles in the image below are the buttons.

This issue is occurring across multiple spreadsheets. I am running Excel 2016 32-bit under Windows 10 on an MS Surface device. It is a monthly-subscription installation so updates are being automatically applied. I can't see anything in the history of
the updates that might obviously be related.
Any advice or news from others suffering the same issue would be appreciated.
David.