Try slacking off the cable and ensuring the master cylinder is all the way out. There's a valve that needs to open to allow fluid to return to the reservoir. When it's open that path should have lower resistance than pushing out the other piston.
Releasing the cable and master cylinder was an immediate game changer.
Thanks all.
@ILb started
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Try slacking off the cable and ensuring the master cylinder is all the way out. There's a valve that needs to open to allow fluid to return to the reservoir. When it's open that path should have lower resistance than pushing out the other piston.