amp-ima-video, 1st pre-rolls "skips/cuts" after 1-2 seconds

@alanorozco
using amp-ima-video.

I’m getting a bit of a weird problem/ bug. If i have 3 pre-rolls, pre-roll 1 loads, then seems to “cut” after about 1-2 secs, then pre-roll 2 starts and plays ok, pre-roll 3 plays ok. We build a vmap off f the bids that come back as we use prebid, amazon, dfp/ adx, so if i drop the vmap link into google “video suite inspector” it seems to play ok, so sort of points me towards maybe a bug or something/ recent chnage in amp-ima=video and the ima sdk it uses?

Start by reproducing the amp-ima-video case with three pre-rolls and compare the VMAP behavior in Google Video Suite Inspector. Investigate the interaction with the IMA SDK and the reported Prebid, Amazon, and DFP/ADX setup; done means the first pre-roll plays past the initial 1–2 seconds before the next one starts.

Written by the indexing model from the issue text.