Track bike transmission issues

This is probably gonna be a long one as I want to include as much information as possible but I'll include a TLDR at the bottom.


Background

So I fairly recently picked up a 2000 Suzuki GSX-R 600 SRAD for use as a track/race bike. It's the real deal, and I got it at a pretty good price due to a change in circumstances with the previous owner. Importantly for this question, it's fitted with a Sigma slipper clutch, a Shifting Controll Quickshifter (upshift only), and the gearing has been setup in the GP Shift pattern.

The bike starts and runs really well, and it's been taken on track twice, for a total time of about 2 hours which is where I started to notice some quite strange issues with my transmission and shifting gears.


Problem(s)

1): Probably the biggest issue I've been facing with this bike is the fact that even if I am at full send in a gear, and I try to engage the QS it will often just go straight into a false neutral (which obviously redlines the engine as I'm still on the throttle). It happens at least 2-3 times per session on track. To the point where I try to shift as little as possible. I know you need to be quite forceful with a QS but this seems to happen if I force it in, slowly walk it in, or just shift as I normally would on my road bike. After going into false neutral I'll let the throttle off slightly and it'll jump into the correct gear, unsettling the bike.

2): On top of point 1, sometimes my gear lever will just have tons of resistance and not want to go up into the next gear at all, like it's in 6th and there's no more gears left. I either then have to use the clutch or keep the gas on and try again with the QS a couple of seconds later, where it will usually work (or hit a false neutral).

3): Even if it decides not to go to neutral it's rare that I get an QS upshift that doesn't clunk into place. It's not very smooth most of the time unless I am at full send down the back straight. Anything that isn't that with clunk loudly or just not want to shift at all like in point 2.

4): Finally in an effort to avoid the above issues, I started just using the clutch for all shifting, but still I had issues with false neutrals, not as often however. Strangely, when going down the back straight on one session, I shifted down for the corner and hit a false neutral, which jumped into back into the correct gear once I let the clutch out and pulled it back in again. Could be a red-herring but I called it quits after that and didn't risk taking it out again.

Also - when the bike is on a rear paddock stand and gears are engaged with the engine running it is quite jerky and jumps into gear. Even with the clutch. Although I don't think that is related.

What it could be?

I'm sort of at a loss to be honest, I'm not a total beginner when it comes to working on my bikes, but transmission is something I've never really messed with before. And this is the most temperamental setup I've ever ridden. I have absolutely 0 confidence when riding on track, as I can't trust whether the thing is going to go into gear, or slip into a lower gear and spit me off etc. Obviously not good for track times.

Obviously, the clutch is the main suspect in this, all signs point in that area, but as far as I'm aware it's quite new and of good quality so I don't see how it could go so soon. Either that or there's something really wrong with my transmission, damaged forks or misaligned dogs or something.

I did notice that the chain was a little tight, when I was looking over it tonight, but not sure this would cause the issues I've been having. It might even be down to the nature of Quickshifters, this is the first bike I've ridden with one, but it feels like something isn't right.


TLDR;

Bike (fitted with slipper clutch and QS) has some weird transmission issues. Will often clunk into gear, go straight into a false neutral (before jumping into the correct gear off gas), or just feel like it can't shift up at all as if I was in 6th. Even using the clutch does not remedy all of the issues all of the time, just kinda mitigates them slightly. Basically just generally inconsistent and untrustworthy, and not ideal for track riding.

Anyway, that's pretty much all the info I can give on this, hope someones had something like this before, or can even just point me in the right direction. I will go to a mechanic if I need to, but would be good to see if I can sort it myself first.

Cheers