A sales user is assigned to a permission set group that gives them Modify All...

Permission set groups are a combination of permission sets that grant users access to various tools and functions. Muting permission sets are used to remove access that is granted by other permission sets in the group. However, muting permission sets cannot remove object-level access that is granted by Modify All or View All permissions. Therefore, if a user is assigned to a permission set group that gives them Modify All access to Accounts, a muting permission set that mutes Delete access on Account will not have any effect. The user will still have Modify All access on the Account object, which includes Delete access. References: https://help.salesforce.com/s/articleView?id=sf.perm_sets_groups_muting.htm &type=5