Buttons with drop shadow not rendering correctly in Chrome.

Hi,

I've come across an issue with drop shadow buttons not rendering correctly.

When published and viewed in Chrome (87.0.4280.66) it looks like this: 

But like this in Storyline:

I think this is a browser issue as looking back at previous courses that were published several months ago, the same issue is occurring in Chrome.

The buttons were rendering correctly at the time of publishing in September.

 

The same courses when viewed in MS Edge (44.18362.449.0), render correctly.
I first noticed the issue on Friday 19th Nov.

Until today I was using Storyline V3.43.22859, but have since updated to V.3.46.23620.

R.