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What game are you testing this in? I've been able to verify that this is in fact the correct behaviour in Gens 5 through 8. I don't have a test setup in Gen 9, but I imagine it's quite likely to be the same there too.
How are you bypassing Own Tempo to inflict confusion? With Mold Breaker Swagger, the Persim Berry held by Own Tempo Slowbro is eaten before Own Tempo activates.
That's a completely different situation. If your Pokémon has Mold Breaker, the Persim Berry will only activate because Own Tempo is still being ignored. However, the sentence on Bulbapedia makes it sound like the Persim Berry would prevent confusion before Own Tempo does, wasting your item.
Similarly, if you burn a Pokémon with Magma Armor or Thermal Exchange using a Mold Breaker Pokémon, a Rawst Berry would probably activate first.