I'll be drilling air holes into the totes, it's possible that they were still rather moist at the bottom of the totes even though they were cracker dry at the tops
Yes, you need ventilation in the mini-greenhouse totes. But I do recommend watching that YouTube video that I linked to because he walks you through the concept that you drill a vent hole in the bottom sidewall of the tote on one side, and then drill another hole on the opposite sidewall towards the top. That creates a natural path for the air to flow from the lower, cooler vent hole out the higher, warmer, vent hole on the opposite side.
He warns not to drill vent holes in the top of the inverted tote, because it would let rainwater in and could potentially flood out your plants. There are many YouTube videos showing you to drill holes in the top of the inverted tote, but I personally disagree with that because of the flooding issue. In any case, with the vent holes in the sidewalls, I have never had any of my mini greenhouses flood out if it rains.
Also, I never drill any drain holes in the tote lid, which becomes the bottom tray of the mini greenhouse when you invert the tote. I bottom water my net cups and pots and that lid needs to be watertight.
I would also mention that I use those tote lids as my seed starting trays instead of the cheaper, thinner, standard 10X20 trays you get in the garden center. When it comes time to start to bring the plants outside for sunshine and/or hardening off, you can easily put on the clear tote as a mini-greenhouse or take it off to let the plants harden off in the breeze. For me, those Hefty Hi Rise tote lids work much better than the 10X20 trays I used in the past.