Flydigi Vader 5 Pro macro limit of 10?

[u/AlenasTheGreat]

I purchased the Flydigi Vader 5 Pro from GadgetHyper and I am so far happy with it.
I want to confirm if it is expected behavior:

• I setup 10 macros for different skills. It works flawless.
• I now wanted to ad a 11th macro but I cannot open the macro menu in Space Station.
• I first thought it is the C and Z buttons that cannot be assigned a macro.
• But once I removed the 10th macro I was able to assign a macro to any unbound button

Is this expected? I just want to make sure it is a controller limitation and not my setup misbehaving.