Causes of Rotary engine failure

[NoDOHC]

I would make this a poll, but I would be sure to miss some common failure mode, so I will not do so.

Here is what I have found:

Gradual Loss of compression:

Caused by:
Chrome Flaking (Primarily effecting 12As, pre-'86 13Bs) - Also seen some on S4s.
Corner seal chipping -housing wears to allow corner seal to overextend, it get crooked and ruins side plate (Typically seen on S4 NAs, although I just found an S5 with the initial stages of it).

Oil Seal Failure:

Caused By:
Dirty oil
Overrevving when cold
Age

Naturally aspirated:

S4 engines lose coolant seals:
Caused by:
Improper antifreeze
Housing corrosion (improper antifreeze or old age)
Age of seals (brittle)
Overheating
housing material composition/porosity issues

S5 engines lose coolant seals:
Caused by:
Overheating
Age of seals (brittle)
(I have not seen the other failure modes for an S5)

Engine seizes:
Caused by:
Running out of oil (I have never seen this one, but it must exist)
Oil pickup tube coming off
Sitting too long and having carbon buildup jam an apex seal, preventing the engine from rotating
Carbon buildup in intake ports (especially the 6PI of the front rotor) coming loose and jamming in the combustion chamber as the rotor passes TDC
Massive apex seal failure
OMP failure and no premix (never seen, but must exist)
Fasteners dropped down the intake

Apex Seal Failure:
Caused by:
Excessive wear (especially on the pre-'86 13Bs and 12As @ > 200,000 miles)
Carbon buildup breaking loose as a chunk and going through the engine
Carbon buildup on spark plug catches apex seal and nicks the center, starting a scoring pattern on the housing
Fasteners dropped down the intake
Excessive Nitrous Oxide use

Turbo (this is where my experience is much more limited):
S4 coolant seal failure:
(same as NA)
S5 coolant seal failure:
(same as NA)

Engine seizes:
Running out of oil
Oil pickup tube falling off

Apex seal failure:
Most common cause is stock ECU cutting fuel to rear rotor during an overboost condition. Frequently caused by exhaust upgrades or lack of exhaust maintenance.
Detonation under boost (Carbon buildup decreases detonation resistance over time)
Lean detonation due to fuel starvation (plugged filter or empty tank)
Pre-ignition caused by improper tuning/ECU spark timing errors.

Side seal failure:
Improper Porting techniques/Improper Port size
Severe overheating
Carbon Buildup

Turbo failure:
Oil Seals (fills intercooler with oil sludge, smokes really bad, can kill engine with carbon lock)
Bearings (usually on a modified car (FCD, etc.))
Exhaust turbine (Never seen, but must exist)
compressor wheel:
Corrosion/pitting
fasteners going through the turbo
Nut coming loose (only heard of once, on rebuilt turbo)

The purpose of this thread is to build a list of common failures to help those who have not yet had them to avoid them.

If you have maintenance procedures that avoid these failures, please include them too.

Thanks for the excellent input so far!

Please continue to contribute, I think this would be a service to the rotary community.

This list may become a mess, suggestions for better sorting are also welcome (Generation Specific / Failure with generation description / etc.).