I'm of the opinion that dishonesty is serious because it's an irreconcilable breach of trust. There are many things I'm happy to deal with internally providing there's a frank account but once someone intentionally misleads another it makes individual management untenable.
Separately it's a HR problem because of the nature of certain types of work. I'm struggling to fit my view with neural diversity though - some devs say dishonest things without malicious intent because they lack skills to effectively communicate.
Sometimes people reframe mistakes or lapses in a "dishonest" way to save face. I think it's important to use those occurrences as opportunities to show that it's safe to be honest instead. Allow them to come clean and show that the highest priority is correcting the problem. Running straight to HR instead of creating a teaching moment could increase distrust and the incentive to be dishonest.
There is a line between this and manipulative dishonesty, of course. Bad faith (when it's clearly that beyond reasonable doubt) should be treated with close to zero tolerance.
Separately it's a HR problem because of the nature of certain types of work. I'm struggling to fit my view with neural diversity though - some devs say dishonest things without malicious intent because they lack skills to effectively communicate.