i'll try to answer
What transactions?
Every update is a transaction. So every update can potentially be a problem.
By "randomly" you mean you have no idea what's causing it?
No, simply the solving approach, for now, is a workaround. So we can't know before which transaction will break next time.
Take care that is not everytime space problem, but due to it, it may happens that it lose data consistency so next time an update run, we can have another kind of issue.
due to today, we're planning to schedule a meeting to analyze deeply this situation and have better ideas on a good solution.