nefarius I'm constantly getting the memory message using the app and Chrome browser on android. I have had the same on 2 different phones - a 1GB and a 4GB.
I thought it was the cheap phone until I tried the 4GB one. Also I have searched and found loads of advice about that message. But it isn't consistent.
So I'm still not sure if it's a browser issue or the forum software.
Finally, I have found that switching away from the giffgaff app to get a picture or some information from Google often causes the app to logout or drop a reply I'm in the middle of. So that leads me to think that there might be a memory issue with Flarum. I'll keep an eye on this and post more as and when I get any more useful information.
PS - including a screenshot of the reaction button and Reply link led to minutes of tapping the screen madly and swearing profusely. For the avoidance of doubt, this is definitely user failure not a giffgaff issue.