I can't talk directly about commercially made Rodinal clones (though I doubt it's a myth for them, either), but Parodinal (homebrewed work-alike) certainly does support one hour stand development -- I've done it. Now, I can't say it isn't doing all its real work in the first 15-30 minutes (at 1:100 dilution, it would run above 15 minutes with normal agitation anyway), and then dying -- but that's partially the point of stand development: local exhaustion, to limit contrast (especially by shouldering off very high exposure) and produce edge effects that enhance apparent sharpness.
Now, I've never mixed working solution Parodinal and then left it to stand in the graduate for more than long enough to fill the stop bath and fixer graduates, verify temperature, and set the timer -- but at 1:25 or 1:50 I wouldn't expect thirty minutes to be a problem. I've left Caffenol (the non-ascorbate original version, which is completely free of preservatives) for fifteen minutes or more, to settle micro-bubbles from the laundry soda, and it works fine -- though I don't know of any reason I'd leave it for an hour, since it doesn't lend itself as much to stand development.