I do not believe telemetries are actually implemented on the switches, even though call out in the on-line documentation. At least for EX4200-PX I know it is not there.
Also I believe I've seen situations where the switches either ignore or do not respond to LLDP-MED, and therefore use Class detection as the determination of max wattage. You can overcome this by hard setting a static max wattage value as @arulav stated. I would try this first to see if that makes them work.
Please note I have experience only with Avaya 9600s (higher grade, more costly??) which work fine with all Juniper EX switches, old and new.
Good luck.