Never had issues on .156 and after updating to .158 they continue to respond and be fully reliable.
I am currently using more than eight and find them absolutely reliable.
Mine is a mesh mostly depending on Zigbee devices all throughout my home with lots of them acting as repeaters. (And a few Z-Wave.)
I believe that when failing, it is not an issue of the Hue 4 button dimmer, it is an issue of the local mesh (or the battery).
