Ion xe20 submasters crash

Ok this happened 3 times now in 2 weeks , twice during a late night programming session and now tonight during a show. Sub levels froze on stage and didn't realise until before a  B/O.  By the time next B/O came around I had figured sub 1 thru 20 out would do it. Presto. But now the subs are still unresponsive, with the values on LCD staying at 0% when pushed up.

Turning off /On the console will restore it to working order.

Log attached.

Any ideas?

Ion xe20 running 2.6.3.9.0.2

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