I am on 8.3.28 and it appears to be doing the same here. I even waited for a while refreshing the folder containing the uploaded test attachment. I would keep an eye if it does disappear after a few hours!
I tested a video file, if it matters, as it's easier to locate on R2 than to test an image attachment.
If not a PHP 8.3/8.5 issue, could it be XF 2.3.8?
i do not think so except for this one. i only have it enabled for a few members and it is rarely used. reason why i never bothered to check this before lol.
It would be really nice to see in the CF analytics widget if AI bots are throwing a party on my site...
CloudFlare has AI Crawl Control Metrics. I found that Meta AI was getting ridiculous and needed to be blocked.