Heart Rate Monitor Reaction?

[Catrin]

I've been using a Polar HRM for most of the last 2.5 years - and I've always used it for all of my fitness activities. Of course it isn't the same strap, and indeed I replaced my HRM entirely at the end of the year.

Nothing has changed in my use of it, but I am noticing an odd skin reaction under the strap where the battery/transmitter contacts are. This makes no sense to me - the actual contacts aren't on the skin side I've got a few red welts that almost look like blisters and could be very small ones...but it is ONLY under the area of the strap where the transmitter/battery contact is. I would think if it were a chafing/sweat thing that it would cover a larger (or longer) area. This has happened a couple of times in a row now, so I guess I need to figure this out.

Has anyone else experienced this and found a way to solve it? Just to test my observation, when I ride tomorrow afternoon I will wear it differently and place the batter/transmitter section around closer to my side.