The consecutive match cap was never officially announced by Ludia, however, one of the WotC insiders identified this change in a forum post shortly after one of the updates last year. The cap of two consecutive matches may have only applied to ‘Battle Mode’. I have also been informed it could be overridden by selecting ‘Wait’ as opposed to ‘Battle Now’ when the option arises.
Generally, I avoid PvP events and always select ‘Battle Now’ instead of ‘Wait’. With this in mind, I had not been matched against the same opponent more than twice consecutively, until the recent update. The only exception I can recall was one weekend late last year when the matchmaking formula went awry. For a few days significant mismatches were the norm and extended consecutive runs against the same opponent were common.