What happens to a reentry permit when a foreigner is waiting for visa extension approval in Thailand?

Just need to clarify situation with reentry permit. I read somewhere in the groups, if foreigner applied to next extension and "under consideration" stamp, then in case he/she had unused single / or multiple reentry permit before extension application, then this permit become invalid. Then if need to travel overseas when "under consideration" (which may be as long as 30/45 days depending on province), will need to buy new reentry permit (most probably single as it can be used only in these 30/45 days, no reason to do multiple before next extension granted).

This is interesting situation and I not yet had experience to travel overseas when "under consideration". Will be glad to get correct information about this.