E6 development: Underexposed or underdeveloped (FD)?

I just developed my first roll of E6 film (it is 120 velvia), but the slides came out waaay too dark. I used a jobo processor and made sure the temperatures of the solutions were 38", and kept time quite precisely. I normally do c41 with excellent results. I used the times indicated by the Tetenal kit.
But... I'm not sure it is a development fault! If a lab returned this I would just think I underexposed them. Can someone with a better eye for slides help me out what could be wrong here?
The frames are super dark, but the edge markings seem ok. In comparison there is a lab-developed (slightly overexposed) precisa 100. The colors don't seems off, and I even managed to make a contact print from it.
I have other 4 rolls to develop, and I don't want to just increment FD time to discover this roll was indeed underexposed.
Thanks!

The film codes on the edges are bright and clear, so i think it was developed properly. Maybe it really was underexposed.

I recently got back a velvia that was slightly underdeveloped. I could tell easily because the metadata that my camera prints between frames were darker than usual.

You should also ask around here about FD times. I remember clearly reading that FD time should be extended for certain combinations of chemistry and film brands.

Difficult to see the sample image clearly on phone at the moment but they do appear grossly underexposed at first sight, assuming care with development and fresh chems. Shooting conditions? Check your ISO setting at the camera as a first line of enquiry. RVP50 tolerates well 0.3 stop up/down but anything over +0.5 or +0.6 will show pronounced underexposure and thick, undetailed shadow with an overall very dark appearance. Did you keep notes of your exposures?

The 35mm E6 strip behind the 120 appears nondescript exposure-wise.

FD development time should be 07:00 for Fuji E6 film which applies to Agfa E6 film as well. ISO should be 40 for RVP50 and 80 for RVP100.

Thank you guys for the feedback! I'm convinced now it was my exposure at fault, I ran two other rolls (an aviphot 200 and a agfa/fugi 100), exposed with a cam I'm 100% sure the meter is ok, and the results are beautiful. This velvia was metered with my handheld meter and I must have screwed something, even if I always had good results with negative film.
I'm not convinced about the 7:00 FD for Fuji film, I find it mentioned nowhere in newer manuals and documents (I suppose Tetenal would make a note in the booklet since Fuji is basically the only slide film manufacturer left...), just in very old literature. When I have a roll to spare I will test different times.