I didn’t add enough water to canner, it started acting strange and so I shut it down 20 minutes early. So do I need to restart for the entire length of process? Do I need to change the lids even if sealed?
With loss of water in the canner, the canning process is stopped. The canner must be reopened, with no pressure remaining in it. Remove the jars. Do make sure the bottom of the pressure cooker/canner is flat. If it was dry too long the heat will distress the metal and warp it which causes the canner to no longer be safe to use.
If the canner is flat on the bottom, add about 3 quarts of hot water into the canner.
Remove lids from the jars and put on new ones. Return to canner. Reprocess with the the entire amount of time and procedures.