My 1100 does that if i go full open from idle. No issue when whiping the throttle open from 2.5K RPM and above.
I noticed it after the swingarm maintenance. Only issue is that I had the bike since 3 weeks and I don't know if it didn't do it before or if I just didn't notice it.
The only thing I did during that maintenance that could affect the motor is that I removed the pipes. I tried to look for leaks, changed the exhaust gaskets, reseated the air filter, tried both the agostini and stock muffler but the problem is still there. I run a beetle map.
I stopped worring about it since I can't really feel it while driving.