I’ve been importing a lot of old pictures from my Flickr account and consistently keep getting 504 Gateway Time-out errors when importing more than just a handful at a time. This happens on different computers/networks, at least one of which is using high-speed internet access.
Despite the error, the import seems to go through ok and eventually will appear when I reload my observation list. Sometimes it can take a few minutes. At first I thought the import failed and went back to try again, which then resulted in duplicates I had to clean up, so just a heads-up to anyone trying the same.
Yes, I have had the exact same experience for as long as I have been on iNaturalist. I’ve always assumed that it’s more of a browser-server communication issue than a bug within iNaturalist itself, but I may not know what I am talking about.
I’ve developed the habit of keeping my observations page open in a separate browser tab, then after the 504 error happens, I refresh the observations tab every once in a while. Usually after 10 or 15 minutes (depending on my batch size), all the observations will have shown up, slowly but surely. If some are still missing after an hour or more, it may be due to a legitimate error (like >750 bytes of tags, which sometimes happens to me).