Effects on A Mono Bus (Group) Track are Blacked Out

Hey Everyone,

I’m pretty new to Cubase, so I’m not fully familiar with how Group-Bus tracks work.
So, I have a variety of different Lead vocals recorded and put into a folder, I then want to route all these vocals to one bus. I do that by selecting them and going to the mixer, and then creating a group channel for all of them so that when I check the routing they all have the output to that bus which was initially in stereo but I put it in mono.
However, when I try to load a plugin chain I saved for my vocals it blacks out some of them while the others remain active. I initially thought it did this for mono versions of the plugins when I had a stereo bus, hence, I changed it to mono. That didn’t affect it, and, if I select the same plugin but in stereo it also blacks it out, making it unusable. When I click on it, it doesn’t open; it’s just frozen.
Anyone knows how to fix this?

I included a picture below to clarify.

Regards,
Nick

Is Constrain Delay Compensation turned on?

Hey, yes it is as otherwise, the vocals are offbeat with the instrumental.
Is that the reason why?
And why would it be solely on the bus-group track as the inserts on the lead vocal track itself are not blacked out? Or is there a limit once constrain delay compensation is turned on?