Hi,
I've noticed this issue for a little while now. When you export a file from Premiere Pro and the 'Export' panel loads up. The export panel has loaded with my export preset 'AD AS-11'
This should be AVC-Intra 100 1080i 25 fps.
However, the export panel is by default going to export the sequence as 720x486 29.97fps.
Only by re-selecting the preset from the drop-down menu does the correct preset settings lock in.
It doesn't happen every single time - once corrected, it appears to stick for a while.
Sporadically, the 'Export' panel appears to just pick a random set of export settings that are not true to the preset loaded.