I have done several tests now, and the results are consistent:
 
Using Concrete Limiter in ProChannel, and setting the out ceiling to -0.1 db, it consistently goes over if pushed hard enough.
 
Maybe it's just me, but it seems that "concrete" in this case should mean that there are no peaks over this level.
 
Can anyone comment or replicate?
 
Note: this was done taking a 44.1kHz mix and upsampling it to 96 kHz.

Last person who reported this actually had his ProChannel pre fx bin and was running some fx after the CL by accident.

Is the CL's own meter reporting this or the track meter?

Sanderxpander
Last person who reported this actually had his ProChannel pre fx bin and was running some fx after the CL by accident.

Is the CL's own meter reporting this or the track meter?

I was going to recommend the same thing.  

Strangely - no. No clips reported on the metering - but the exported file has overs.
 
I'll keep investigating.

Did you check if you had plugins in the FX bin and if PC is post FX bin?

And if your export bus is at 0 or lower and has no automation on it making it go higher.

No automation on the bus level; no efx post the Concrete Limiter.
 
The mystery remains.

Be sure that all your tracks go through the buss with CL on it. If its an export be sure that FX is checked in the export dialog. 

Almost every limiter when pushed over its limits will clip. Especially when the attack and release settings are wrong for that audio. What makes this limiter different from the others, especially the  better limiters that are out there??
 
To solve it, Back off your signal or use a better limiter and one that has ISP detection and oversampling.
 
CJ

Well for one it has a look ahead buffer. It should be very hard for it to fail. I have never had a problem with it but I don't as a rule over drive it either.