I posted a response a few months back and looking at the picture that Jacojet has posted. I am more sure of what I posted now more than ever. It is very simply "blade creep" I suspect that the metal in the compresssor is not of a strong enough alloy to prevent creep. It is evident that you can see compressor case fretting from the compressor blades contacting the case. What Wren needs to do is go with a stronger metal such as Titanium etc. As I stated earlier the owner of the engine needs to take a feeler gauge and get a measurement between the compressor blade tips and the case to ensure there is clearance. In essence if the clearances are too tight and the compressor blades touch the compressor case at speed they are going to drag and eventually you are going to have liberation of some blades.

I am an A&P and we had a similar problem years ago when the first versions of the PT-6 came out. During trend analysis an engine over time is supposed to degrade in performance. The PT6 engine (1st version) would during trend analysis get stronger through it's life cycle. What we found was the compressor blades had creep and as such we had a few "FOD" events. Same thing here is happening.

Now it is up to Wren to get this sorted out or not.

Regards
Glenn Williams