Hemera Drive Gears Rust and Grinding the Heatsink

I recently had the pleasure of disassembling the Hemera to troubleshoot some under extrusion issues that popped up. I was worried that perhaps I received a unit that had the broken gear problem. I was relieved to find that the gear was intact however I noticed some brown corrosion/rust between the teeth as some other posts mentioned. I dropped a bit of 3-in-1 oil in those gears to hopefully help with that problem, careful not to get any oil into the drive gears.

Anyway upon assembly, I noticed that there is no hard limit to prevent the idling drive gear from contacting the heat sink where the heatbreak threads into. This essentially allows the drive gear to grind the heat sink housing. After looking closely at the construction, there does not appear to be any mechanism to limit the motion of the idling gear to prevent this. Also, the heatbreak extends partially into the cavity and requires me to partially unscrew the heatbreak in order to assemble and disassemble the unit. I'm not sure if this is intended or not.

I suspect that if/when a section of filament that is undersized reaches the extruder, the force of the idling spring may result in the drive gear grinding against the heat-sink/heatbreak and come to a stop. There does not seem to be any built-in machining or material that provides some kind of a stop mechanism.

Anyone else discover this issue? Thoughts?