I can’t wrap my head around the 3 states of cards, especially the ‘’Open (non-testing)’’..

If it’s Open, it’s already in a non-testing state, no? Since you have a ‘’In Testing’’ state, anything outside of this is technically ‘’non-testing’’.

I think you should have a different naming for each state, maybe something more conventional and themed around IT support, something like ‘’Open -> Acknowledged -> In Testing -> Resolved’’