Had the same issue once on my 2011 Gemini
Cat. Alarm turned off sometimes, stayed on other times then quit. Finally settled into never shut off.
Found loose connector at oil
. Was bouncing around due to engine movement, sometimes contacting, other times not. Finally just came completely loose and swung away from sensor. Thus no shut off.
The connector boot hid the "loose" condition yet kept the connector close enough that engine movement could cause intermittent contact.
Check your connections by physically pushing/pulling connectors. I have even had what looked like good connections come apart when pulled slightly.
Good luck finding the culprit.