Last night I started noticing these errors.
My meteor sites have not been rebuilt or re-deployed for weeks, so I can’t imagine its actually a Meteor issue, but the issue only started after i made some tweaks to my reverse proxy pointing to my site. In tracking it down I noticed that some of my images were now rotated as well, and determined that my version of chrome was also upgraded to Version 81.0.4044.92 (Official Build) (64-bit) (which handles image orientations differently now). Restoring my reverse-proxy to the way it was last week did not resolve the problems.
Have others seen these SourceMap issues with the latest Chrome?
By the way, I have now fixed the image rotation issues with ‘image-orientation: none’ at the top of my css.