Technican Appear in drop down list while creating a ticket but it doesnt exist as a real technician

Technican Appear in drop down list while creating a ticket but it doesnt exist as a real technician

We are currently experiencing and issue when trying to select a technician who appears in the pick list but doesn't actually have a real tech accounts how can we remove this bug.

Our Current Your Version : 9.1 Build  9120

We will be updated to latest version soon but in the meantime we need to fix this issue before that happens.

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