Hi @oferc1,
I'm no longer working in the Kaltura player project.
You can try and contact @oren_melamed for player related questions.
Seems that the VPAID support is not working as it should in 2.48.3 - this should be checked by the player team.
Did you try using the doubleClick plugin instead of the VAST plugin? You can put your VPAID URL in the adTagUrl property of the doubleClick plugin and it should work.
Thanks,
Amir