I think this has been going on for a few weeks at least, but I’m pretty sure this hasn’t always been a problem. This seems to be observation-specific, although the same issue doesn’t always happen with the same observation. I’ve never had a problem when opening maps from my own observations. I haven’t noticed any patterns for the observations that do have problems.
Does this ever happen on the first observation you tap on? Especially the first one you tap on after you force quit and reopen the app? It seems like maybe an out of memory issue.
The next time this happens, can you please re-open the app and send us log files? To send log files, go to the About tab in the iNaturalist app and tap three times on the version number. You will then have the option to email the log files to us. Thanks!