T46 Phone SLOW/HANG issues

[JSM Communications]

Not only the T46 has this issue!

We have multiple clients complaining that their phones (T42: 29.80.0.95) are very slow in reaction time.
Mostly when they transfer calls internally they have a 1-4 seconds delay answering the call. (1-4 seconds before they hear the other side of the line)

The clients work on a separate internet line for VOIP, so no data network can interfer with the connection.

Our clients didnt have this problem with older firmware (firmware that came with the phone x.x.188.x), so we are pretty sure this is firmware related.

Is their a solution for this problem? Or do other people have this aswell?

Thanks in advance,
Nathan.