First question - Can you have more than one side mission from a Corp/Group at the same time?

I've run into three bugs with side missions on three normal missions in a row.

The first one was to be monitored by Chimera by wearing one of their pieces of gear as an accessory on my next mission. One of my characters wore it, but then I didn't put them on the mission. I had to report that I lost the device. They gave me another one. I wore them both on my next mission, and still did not get credit for it. My Cyberninja was still nauseous at the end of the mission, and that condition could not get cleared up by the Medbay. (I had to use one of the Cerulean Crystals from a mine to get rid of that condition...see below for my problem with that mission.)

Next, I was on a mission with Rhyzsom (spelling?) to get daata from the mainframes in the server rooms. The next mission that I took was to secure some device in one of their labs that had been overrun by native lifeforms. I got to the server room, but there was no way to access their mainframe. Was this because it was one of their facilities?

Finally, I'm on a mission in a set of mines, and I have the side mission from HEHS to sabotage three mining drills. I have been able to sabotage two of them with no problems. I have the third one right in front of me, but I cannot activate it. I can step on the square that the drill is on, but that doesn't seem to do anything either. it's in front of one of the chunky rock texture squares.

Has anyone else run into any of these issues?

Yes. Well, you have broken the quest there. Does the gear still exist after the mission that you should have gone on but didn't? If it does, what happens if you use it on another mission? No idea but I doubt it.

The data access is via a second, dedicated terminal in the same server room. (If you try to access it without permission, before taking the quest, it just tells you there is nothing there.) Sounds like a clipping issue. (The Unity engine is owned by a third party.) Just restart the mission, if you can, or start from wherever and try again. There are numerous little bugs in the game, still, but nothing should break the game. Try and remember that —— whatever you are trying to do —— the developer has had to think of it first to programme a response to it, and if you happen to do something in a manner that they didn't think of then the game won't be programmed to respond correctly.