Microgreen peas mould

I've been doing microgreen peas for a few months now off and on and ive managed to get some good harvests from them but lately, the last 4 batches I've tried have got mould while under blackout so I've had to bin the lot, the only thing that's changed is the humidity so I put them somewhere cooler but they still got mould in them after 3 days. I've used moles seeds and Sutton seeds so can't just be a manufacturing issue. Any ideas / advice on what to try?