If the issue is being seen with latest firmware available on cisco.com for this 8821 then you should open a TAC SR to see if there is any internal ES firmware that can be tried. There are numerous bugs related to phone restart/crah for 8821 but none matches your scenario exactly
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvc56148/?reffering_site=dumpcr
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvc35996/?reffering_site=dumpcr
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvd68239/?reffering_site=dumpcr
Manish
- Do rate helpful posts -