Kegged beer taste funny?

I have kegged my last 2 batches and also bottled about a gallon of each. The bottled beer tastes ALOT better and the kegged beer tastes almost contaminated-ish.
I sanitized both very good before racking and cant figure out why the kegged beer tastes different. I have 2 kegs @ 40 degrees and set to about 12 psi. The carb level is good but I can taste what I consider a "gassy" taste. I have made sure both kegs have a good seal and there are no leaks in any of the lines.
Any ideas why I could be getting an off taste with the kegged beer? Any help would be greatly appreciated!

what do you use to clean the kegs with? not sanitize,but clean.

Did you disassemble the kegs including the posts?

Did you dissemble the posts and clean the posts, pipits and change the o rings?

Did you purge the o2 out of the keg after you gassed it up?

What did you use to lube the seals?

I cleaned the keg with just the sanitizer solution and a clean rag. The posts were taken off and o rings replaced when I bought the kegs. I did purge several times to make sure all of the o2 was out. I have not lubed the seals with anything since there they are not leaking.

My turn for questions!

How long has it been at 12 psi at 40 degrees?

I'm thinking it's "fresh" carbonation. Carbonic acid definitely has a "bite" that settles down after a week or two.

Are you using food grade CO2? From what I understand, there is a difference. Food grade CO2 is more pure in form than non-food grade, and non-food grade can cause weird flavors. When I bought my tank, they specifically asked me if it was for use with beverage dispensing.

I had the co2 filled at a beverage supply store. He did not ask if I needed food grade co2 but we talked about kegging beer and he knew what I was using it for.
The last keg I had was a Fat Tire which I set @ 10 psi and left it. This batch is a Rye IPA that has been in the keg for 8 days and is carbonated but has the same off taste the other keg had (they are different kegs.) It could be that it just needs to sit for a while longer but the first keg had the same taste after sitting for 3 weeks.

Should I clean the keg with anything other than sanitizer?
Should the o rings always be lubed even if they are not leaking?

That all sounds ok.

so now we need to know if you can describe "funny". Funny tasting, how? Acidic? Plastic? Sour? Tart? Ashy?

It's hard to describe the taste but it just has an extra bite the bottles dont have. I thought it may just be overcarbonated but I dont think that's the problem.