Comment (by Samuel Cupp):

As requested, proposed fix simply removes the assert, as the function->RDWR element is not actually used anywhere in the function. As the function always returns true unless presync_mode="presync-only, there’s no problems with this.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2781/fix-bug-in-debug-mode-with-presync_mode