Personally, this would make me extra suspicious of him. He’s clearly extremely competent, but if we can take it as given that he’s not going to hold the job for more than a year, then one major possibility is that he’s up to something so bad that they can’t possibly justify keeping him at the school once they find out. Even not knowing that he’s secretly Voldemort, it seems like they have adequate reason to suspect that not investigating into his activities is something they could seriously regret. If he were merely engaged in something harmless but illegal, they could probably brush it under the rug, so they should be prepared for the possibility that it’s something much worse.
Personally, this would make me extra suspicious of him. He’s clearly extremely competent, but if we can take it as given that he’s not going to hold the job for more than a year, then one major possibility is that he’s up to something so bad that they can’t possibly justify keeping him at the school once they find out. Even not knowing that he’s secretly Voldemort, it seems like they have adequate reason to suspect that not investigating into his activities is something they could seriously regret. If he were merely engaged in something harmless but illegal, they could probably brush it under the rug, so they should be prepared for the possibility that it’s something much worse.