This is a Windows handling of "internet shortcuts" problem.. not a Steam problem. Specifically in the way that it handles the icons of custom "internet shortcuts". Every time the icon cache is cleared, it randomly decides a bunch of new icons in which to take the 256 icon and display at the max size of 48x48 (or 64x64). I know that it's using the 256 pixel icon to do this, because I have a different icon for 256 than for everything else. In this case a Youtube thumbnail for 256, and a regular Youtube logo for 64 and 48. It will resize the 256 thumbnail icon but only below it's regular size. That's probably unclear.. so I'll try to clarify.. it's showing it at a quarter of the size and only resizes it in the last 10% of the range (before switching to content view). This is while holding control and mouse scrolling. It seems like it resizes it from 64 down to 48 but it's hard to say the exact number.
It's definitely 'finding' this 256 pixel icon, it's just displaying it too small.. for no apparent reason. Randomly.
It's really easy to pinpoint this and rule out other factors because I have made 100's of icons this year and haven't had any issues until now. Nothing else has changed other than trying to have "multiple" .url shortcuts within the same folder using different custom icons.
Up until now, all of my icons have been dispersed so that it's been 1 shortcut per folder.. or multiple icons using the same icon. This is specifically an internet shortcut + custom icon + lots of icons in the same folder problem.
I really can't see how Task Scheduler can help with this but maybe after some experiments I can learn more about this issue.
At this point it's completely random, and completely frustrating and is 1 of 1000 (growing) reasons why I think Microsoft is dodgy.. but anyway.
I've been thinking about making some custom file extensions for different common websites like IMDB, Wiki and Youtube.. and having additional metadata in the files (that are simply text files that act as INI files) specific to that website, for example views or the channel name for YT.. rating, or starring actors for IMDB. And for these things to show in the 'preview pane'. It's possible to create "preview handlers" for these things. But I can't even think about going forward with that part of things until I find some kind of solution for the icon thing. It's 2018 and I'm anticipating that no one has ever found an solution for this and that Microsoft has never even looked at it. Either way.. I will try.
I don't have high hopes but I'll post something if I have any success.