Taking breaks during the bike portion - similar benefit as walking some water stops on run??

I notice this effect as well.  I do make every effort to stop as little as possible in training so my body doesn't get used to it.  But, the inevitable potty break, map check stop, or stop at an intersection to wait for traffic still happens.

I shoot for one stop on the IM....I try to hit the bathroom at special needs so it's the only stop I make but it's "long" enough that I get that little boost.  I guess maybe if I was feeling bad I would think about another potty break near the end of the bike.  It's gonna happen in T2 or on the run anyway so it doesn't really matter when I hit the bathroom (unless you are really picky on how your splits look...I'll admit I've been vain enough to want to use the potty in T2 so neither my run or bike gets the few minutes added).

I stop in training as needed for fluid refills and bathroom breaks. Normally on IM bike I don't stop and it never is an issue that I stopped during training.

We triathletes tend to overthink things. I wouldn't plan on taking 2 breaks at your IM bike. Play it by ear. Training and racing are similar but also different. You will tapered and super fit to be ready to race.

Nice job at Eagleman!

I think Lava or Triathlete mag had an article on this exact topic about a year ago. Basically the suggestion was exactly that, take a 1min pedaling break regularly (they actually said at opportune moments, downside of a hill etc) but as close as possible to a regular interval. The idea was to either coast (as on a hill) or let your effort recover a bit at regular intervals to get the same set of benefits you get from run/walk.

I gave it a try during the Lake Stevens HIM last year and I found that with hills etc. regular intervals and "opportune moments" were impossible to manage. After about 10 miles or so I gave up and just rode. Coasting when it seemed appropriate, pedaling for the rest. It might be easier to do this on a relatively flat course, but I found that with any sort of hills, you naturally take breaks every so often anyway and don't really need to rely on any sort of regular interval pattern.