The issue seems to be the way in which ios 18.1.1 reads the information in a pass (.pkpass ) file
On earleir iOS versions, the pass.JSON below would show the departure date on the lockscreen notification for boarding passes (due to the "relevantDate" field). It looks like as of 18.1.1, it no longer does this.
{
...
"semantics": {},
"passTypeIdentifier": "123",
"formatVersion": 1,
"serialNumber": "ABC",
"description": "Description",
"organizationName": "Organization",
"teamIdentifier": "1234567abc",
"sharingProhibited": false,
"userInfo": {},
"relevantDate": "2024-11-30T12:35:00+00:00",
....
}