Every junk call counted as a conversion is a lie you're feeding Smart Bidding. Three articles covering what goes wrong, why it matters, and the exact fix.
3 articles in Google Ads Call Tracking
The 60-second default threshold counts voicemails and wrong numbers as conversions. Here is the data and the fix.
Setting this number wrong is equivalent to redefining "qualified lead." Smart Bidding trains on whatever you define.
A tap-to-call from a search ad and a call after 4 minutes on your site are not the same intent signal.