Good to know- next time either stop or try to slack the chain a bit and correct the shift, then.
I'm rechaining it today (due to a bike boom-related lack of 6-7-8-speed chains in stock, using a 9-speed chain as a stopgap) so I'll check the RD functionality then. If not, well, there's an old Ofmega Premier at a local shop I've been looking at....