MXF: Strange buffering effect

Trying to play an MXF PAL IMX30 file (8 audio channels) it takes at least 10 seconds to start playing. When it start the time counter jumps from 0:00 to 0:10

While its already playing if you change time position on the time bar it freezes again and it takes another 10 secs. It starts playing and the time counter jumps from 5:56 to 6:06 (e.g).

It looks like if it's buffering.