I can only speak for the things I’ve found, but this one’s definitely a Deliberate Creative Decision:
What’s happening here is that there is a noticeable increase in brightness between the first and final frames of this shot, as if someone thought ‘hey, the door is opening but it’s not getting bright enough inside’. The SSE shows no increased brightness.
The post about the Falcon flash frame may be deliberate, but I’d guess that it was just a mistake.
We determined that the missing laser bolts in the X-Wing cockpit were erased by the algorithm used to clean the SSE, so not a creative decision.