hmm maybe try other network setting:
/rate 25000
/snaps 40
/cl_maxpackets 60 or if it dont make lag try higher value 100 or 125

i dont promiss if fix it.

I have that settings and always jumplag the first map i play so i reconnect.

In 1vs1 it's one map jumplag one map no jump lag. For me 1vs1 = jumplag = impossible to play

I have no idea but this is what happens. I join any 1vs1 server, i jumplag, next map i don't, the third map i jumplag and so on.

I think u mean jumplags like little ,,lags'' or just feel u havent good/right jumps in game or sometimes it feels like not smooth jump.
If u noticed u have that jumplags try experiment with it

I know that on 2!S Tag i havent that cuz my ping is cca 50 (playable), on 1vs1 i got 100 ping and same problem like you , but like flex said it is each player problem, cuz you feel lag but u havent it in game (enemy doesnt see u have lags in game). Now we can discuss if u got little jumplags if u have cca 50 ping.
And about resloving this problem. After few tests flex think problem is in ping (latency). If u got higher ping u feel higher lags. And reversed. Also im thinking this problem started in 1.03 version.

So try to make ur network lower or map_restart it fix it - dunno why (maybe unlagged )

ex :
/snaps =20
/cl_maxpackets=30

This is a bug that arrived with 1.03 it didn’t happen in 1.02b .... it also effects weapon switching. It happens to me at only at 1v1. In tdm, freeze and ctf after the first map jumplags go, its not so with 1v1
I think its something to do with the client numbers. I made tdm or clan areana(cant remember which now) with 1v1 client settings and it happened then, after I increased to 2v2 or above it was ok.