HRM-Tri micro cracks always on upper right screw - design flaw or user improper use?

Could this be the issue here? "Likewise, the melted plastic surrounding a metal insert will shrink as it cools, producing a “hoop” stress in the plastic. This hoop stress will be a constant stress on the plastic part throughout the life of the product and possibly result in cracking if the stress is not minimized during the production process." source: https://www.kaysun.com/blog/material-behavior-hoop-stress-and-creep

I have had this same exact issue with every Garmin HRM-Tri I have had so far. I've lost count how many. They always develop cracks around the elevated screw socket, every single one. I've always treated the straps with great care, but after the first time experiencing this I was extra cautious and gentle. Didn't help. Next one developed the same problem. And the next. And the next. This is clearly a design flaw and should be corrected by Garmin. 

Yes, yes, true, but my local Garmin supplier considers that I didn't clean the strap with soap+water and it's not under warranty, also, the strap is from the Fenix 5 Sapphire Bundle, with the watch, the 2nd pin corroded, it's a known issue, but the supplier also considers that I didn't wash the watch with soap+water and cleaned it correctly, also refuses warranty. I contacted the my local customer protection agency, the first case was lost, after almost 3 months, I created a new case, now after 6 months, the agency agrees with the supplier (even if I pointed out that both issues are known and Garmin does not refuse warranty for these exact issues and that are design failures). Now I made a new case to reanalyze my case with the central agency, not the local branch.... So 6 months and counting... time when the watch and strap is in the suppliers service. For training I use a less expensive BLE+ANT strap from Decathlon, I bought it for training because of the long time it took the supplier to replace the strap (at first the strap was sent to me back with the same issue, it was not fixed, had to send it back, it took weeks to get a replacemnt), the Decathlon strap has zero issues after more than 2 years and it's 4 times cheaper... also I bought a new bike computer (for another brand) to use it until the issues are resolved. So yeah, I'm very disappointed in Garmin and how it handles issues, in the end if you buy Garmin products, also buy backup devices because you can't count on Garmin and it's official suppliers :) 

Me too, these are stress fractures. It's a poor design. It's nothing you've done... I've just sent my report to Garmin....

I've now had this same problem with the HRM-Pro. It's the same design, so I was not surprised. I am disappointed that Garmin didn't improve the battery case for this newer model. I've reported this issue to Garmin every single time I've experienced it, they need to know there is a problem with the design and/or manufacturing execution of said design. 

Had mine (HRM Run) since 2017 .. a few days ago I found out, that it had stopped working.

Thought it was the battery but it didnt connect with a new one either. 

Kept on searching google and found out that it has the same crack in the upper right corner -.-

This is really disappointing as it seems to be a quality problem on Garmins side which should have been taken care of in the newer products. 

Apparently mine isnt under warranty anymore so seems like I am out of luck.

Not sure if I'll get another one as these have the same issues or If I switch over to another brand.

Hello G, it's seems to be an issue. It's a shame because it is such a good product when it is working. The old housing was very robust. However they probably can't get the same features to work in the old housing because of the accelerometer for the run dynamics and contacts needed for the swim. All I can suggest is be persistent with Garmin... I will do more research in future on such gadgets.... Good luck G, Jason