55w generally do not last as long as 35w, it’s the reason TRS only
Warranty’s then for 2 years rather than 3 or 5.
FWIW I’ve run DDM and they still work to this day, I’ve run cheap amazon and they suck, I’ve run Morimoto 35 and 55w and hylux 45w. I have DDM ballasts
From over 15 years ago that still work. The issue is mainly output and warmup, the DDM are or used to be DC output ballasts which cause a cooler bulb temp, are less likely to ignite in cooler weather and tend to be below advertised wattage. The Morimoto I’ve had failures in 35w and a 55w ballast but this is out of 5 kits that’s I own. I also have probably 8 kits of DDM (5 being 35w). Being that I run both I will always side with Morimoto due to increased performance and great warranty while still active. You buy HIDs and expect them to at least live for the warranty period which a 55w is at least 2 years, I know they extend it if you buy the kit with the Morimoto bulbs. I’ve stated 3+ years on my 55w elites, I have 3 years on another set but it sees much mess usage.
It might be a bad batch, could be a bad connection, could be stress on the wires who knows. Running cheap bulbs adds stress to the system as well.