Packet name is not displaying for few packets under info column

edit

there is no condition as you mentioned above. it is the first statement under any case statement

case NRACH_INDICATION:
{
    col_add_fstr(pinfo->cinfo, COL_INFO, "%s", "NRACH_INDICATION");
}

...

As all the other dissectors in Wireshark seem to able to update the info column as required, it looks like the issue is in your code. Without access to the source all we can really say is that you aren't calling the function you show when you should be. You'll have to break out a debugger and see what's happening on the frames that are affected.

@Kuru4634: The fact that it's the first statement under the case statement says nothing. The whole switch-case construct could be wrapped in an 'if (tree)' condition. As @grahamb says, without access to your source we cannot tell.