For PEI 3721 - I can only speak for the 737, but an 'INOP' reverser normally has the reverser actuating lever on the throttle wire-locked so it cannot be moved. Of AB I know nothing.
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TwoOneFour's link is interesting and appears to answer an earlier and possibly relevant question about AB throttles:
"In an effort at maintaining directional control, the captain then moved the #1 thrust lever out of reverse and inadvertently moved it to the Take-Off/Go-Around (TOGA) position, while leaving the #2 thrust lever in the full reverse position."
I'm still not sure this movement is possible on a 737 but it appears so on an AB. Whether or not it is relevant we will see but I would suggest it needs to be looked at by AB?