Adding to Dan's comments
You could utilize the software EMC formally Netsight Console and use the "execute command" script tool (right click on the icon and select execute command script and type the following commands (for the ports in question) various times of the day (as it could be a factor of certain timed events) and then compare the files.
set length 0
show port flowcontrol ge.4.7
show port flowcontrol ge.4.26
show port flowcontrol ge.4.38
show port flowcontrol ge.5.34
show port flowcontrol ge.5.36
show port flowcontrol ge.5.38
show port flowcontrol ge.5.46
If you decide to check all of your switches with
set length 0
show port flowcontrol *.*.*
Then download a free tool called examdiff (it has a apple and pear picture) and compare the
files by show differences only between the any 2 collect
Makes life a bit easier
and also note the big picture
it could be a:
1. Mis-configuration of switch
2. Faulty NIC or wiring
3. Cabling
4. Low end PC,
5. Printers that should not be seeing traffic(like Multicast
6. Congestion
7. etc.