It’s great to hear you enjoyed them! They are one of my favorite parts of BA to write, whether it be flashbacks of their first week or flashbacks from the time they were separated.
I can’t say for sure when / if there will be more follow up flashbacks. Each flashback connects to a specific part of the story, and the newest one is from a future storyline where Sam has a slight issue with avoiding a human walking around. Only the future will tell if more come.