Gaining altitude on RTL instead of going down

Hi all,
I have FX-69 FPV eqiupped flying wing with APM2 (3.3.0)+NEO-7M.
Recently I flown to my first 1km heigh and got some troubles switching to RTL mode.
My RTL heigh is set to 100m and i flown a lot of times with no problems, but that day I was going to get my first 1000m altitude - everything was fine, but as soon as I reached 1000m i switched to RTL mode and the plane started gaining altitude on full throttle. I was afraid it will completely drain my battery and switched to manual, lowered my altitude to about 200m, switched to RTL again and this time it worked as expected.
I have double checked my config analyzed logs, but found no glitches. I’m not an expert yet, so I wonder if anyone else experienced such behaviour? I can’t attach my log file because it is too large, but it can be found here: … nd0dk9FSGM This is zipped tlog from the Mission Planner.
This very moment is here (now it is very funny when my onboard camera also died and I was shoked loosing both RTL ability and Video screen. I controlled my plane only using telemetry information on the screen)

Do you have the .log or .bin from the sdcard?

Unfortunately it has been overwriten by my next flights. It is impossibe to connect usb cable without disassembling half of my equipment :frowning:

Are tlog files from MP useless in my case?

Personally I cant read tlogs very well but theres a few people on here who can.