Hi @Anonymous,
Not sure if you have try the direction I provided to solve your problem, something complext in your scenario I could not reproduce on my side, so only a direction I could provide for your reference.
I could only tell you that the following formula has something syntax wrong:
If(!IsBlank(ComboBox1_1.Selected) && IsBlank(ComboBox1.Selected), Distint(Filter(colMember, DepartmentID in multi.ID),Member.DisplayName), !IsBlank(ComboBox1_1.Selected) && !IsBlank(ComboBox1.Selected), Distinct(Filter(colMember, DepartmentID in multi.ID && TeamID in multifilter.ID),Member.DisplayName), IsBlank(ComboBox1.Selected) && IsBlank(ComboBox1_1.Selected),colMember, IsBlank(ComboBox1_1.Selected) && !IsBlank(ComboBox1), Distinct(Filter(colMember, TeamID in multifilter.ID),Member.DisplayName),colMember)
Further, you have multi conditions in your If() statement, which needs you to make sure the each result should be matched in a same data structure, otherwise the if statement does not work.
What's more, hope you could understand that we could not reproduce your issue because there are too many details and related collection.
I could only tell you that, for the Distintc() part, you need to use the ForAll() to evaluate the Value field so that the ComboBox Items could display display name of your Member field.