Yes. I have double SIM in my phone from different carriers.
Their both are active, but for internet, usually, I use only first SIM. For last 2 days (when I see your message and tried to reproduce the problem) internet connection via 3G works properly. Last time when I noticed a problem with it was the beginning of April. Then I use mostly Wi-Fi.
Possibly I faced this problem when I decided to post this topic.
I'll be in the country 12-13 May and can check how it works with EDGE.
Maybe some problem is in moving to other cell or something else cause these days I worked from home and don't move further than 1 km from my apartment.
OK, continue checking and gathering infos/details.