Hey,
I got my tags from RFIDfriend and a working Teddycloud Setup running for around 3 months. The tags are housed in a 3D Printed enclosure with magnet and working fine.
Now I have 3 (out of 10-15 working tags) which seemed to die over time. One a month ago and two of them today. They simply aren’t recognized by the box anymore (which led me to dis- and reassemble the whole thing 
) while all others are still fine. Also can’t scan them with my smartphone (while blank ones are scannable).
As my daughter is only slightly older than 1 year she’s maybe a bit rough to the enclosures. Are those tags susceptible to vibration / shaking? Due to the enclosure they are NOT bent / teared / bitten etc.
Best regards