Ouch, yeah that is definitely by far the weakpoint of current Hifiman design, the part where the screws come out of the headband and into the plastic backside of the extender blocks. It's fairly reliable if you know about it and take extra care not to put stress at those spots when you use the cans, but otherwise it would definitely be the first joint to fail over time. Maybe try contacting EricHD and seeing if you could just buy that specific part off Hifiman through him. Others have had success (e.g. requesting the grill retaining ring which ordinarily isn't sold as parts).
What's the best way to grab the headphones without putting stress on this part? I usually grab the metal rings that screw into the cups to prevent fingerprints from getting on the part that holds the actual driver.