I did the test and could verify that Veeam works exactly like I said.
I've set the Primary Backup (incremental) to start at Tuesday 11:30 PM and the Virtual Full to run at Wednesday. Primary tooks above an hour. So, the Tape Job started at Wednesday an ran the Virtual Full.
In a real situation, I've expected it would only copy the incremental to the tape and just run the Virtual Full after the Primary at Wednesday 11:30 PM.
Therefore, I believe my suggestion will solve this problem because I could set a time at Wednesday to run the Virtual Full (e.g. 12:00 PM). So, if the tape job starts at Wednesday before 12:00 PM, Virtual Full won't be run.
I hope this could be considered in a update soon.