is there congestion in the cell ?
if no:
Perhaps TRX from 1 to 6 are taking all the traffic already, and Nokia TRX allocation algorithm prefers to “reserve” those TRX only if there is more traffic.
if yes:
did you block access to these TRX (preference mark ?) perhaps only PS traffic can be allocated there ?
if you lock other TRX 1…6, can the TRX 7 and 8 carry traffic?
this is a strange case, sorry i can’t help more…
when you say 4/4/4 configuration… what do you mean by TRX 7 and TRX 8 ?? Which cell do they belong to?