Hi Andrey,
It seems you are using 1080p resolution with a lower level (3.0). H264 standard supports only upto 1620 macroblocks for the level 3.0.
Decoded picture buffer limits and all might have set wrt level limits and this can cause buffer issues. Please try setting a level of 4.0. (Level = 40 in config) and see if any issues are there wrt decoding.
Regards
Sudheesh