Bad news. I've left aMule working overnight (when I've left it last night everything was still working as expected) and this morning I've found it struggling: the hard drive didn't stop working a second, upload and download speeds were awful and erratic; I've checked and as expected the swap had given up, I needed to reboot the router because the swapoff command didn't help. EXACTLY as with the other versions from 9838 and so on (some of the older versions tested like the 9624 had a somewhat different behaviour as described in the previous posts but weren't stable anyway).
I can't even imagine what could make the swap crash this way (even considering that the router remains stable and the ADSL carrier up and I can reach any WAN address with no issues).
In response to your question: no, I use the remote GUI only for a couple of minutes to check how things are going on but keep it closed most of the time as I think that establishing and keeping the connection opened is another load for the poor router. I'm starting to think about giving up!

By the way, if you think that it could help, I would build the newest 9963: the bug has been introduced with 9704 and this makes sense but, again, I only use the remote GUI for a couple of minutes, sometimes over the day.
Just a last thing: the italian translation is almost fine but with 9960 (I could be wrong but I don't remember this "issue" with other versions) when I exit aMuleGUI it asks for confirmation in english. It's just a very marginal issue.
-EDIT-
Confirmed: aMuleGUI 9852 (the last before 9960 that I've built, it works so it uses the same protocol version) asks for confirmation in italian, not in english like the 9960. By the way I don't think there is the need to waste time on this.