This issue occurs in two scenarios:
1. When using DFC3 (any type DFC3a, DFC3b, DFC3bxl) and cross module layer2 etherchannels.
2. When using cross-module layer2 etherchannels in supervisor engine fabric connection is in bus (flow-through) mode.
This issue is due to the software bug which is documented in Cisco bug ID CSCee10005.
To resolve the issue do not configure the cross-module etherchannel if the software running on the switch is 12.2(17a)SX01.
Or upgrade the the software to 12.2(18)SXE or above.
The software can be downloaded from LAN Switching Software.