Also encounterd this problem, in the Webview it lagged behind by one Powerpoint slide.. I will use the Webview/main for our livestream in OBS, until I find a better solution..
But for the problem, wouldn't it be enough to just validate if the two slideCounts match? This is no fix for the mid-animation-screenshots, but I think it is not effective to compare the screenshots in javascript.
Maybe there is a better solution, but it would really help all to have a fix:
Sorry for posting it here in the forum, but couldn't find the Webview-Remote from this Version 2.4.6 on gitlab