Tag alarms sometimes reverting to default

Many of our field devices are monitored via Ignition using UDT’s - The UDT is the same for all of these. When a tag alarm is triggered, usually the message that is emailed is correct - the configured alarm for that tag has a custom message and custom subject. However, sometimes I’ll receive a block of email alarms that are generic; ie message will be something like: “At 01:11:01, alarm “High Pressure Alarm” at “” transitioned to Active.”

The configured expressions for the alarms are as follows:
subject: {Gateway}+" “+{label}+” Irrigation Controller HIGH Pressure Alarm"
message: round({[.]Calculated pressure},1)+"PSI measured on “+{label}+ " drip line header. Risk of line blow-out. Please check!”

Is it possible that something is going on with {Gateway} or {label}? has anyone seen anything similar to this?


Just an update in case anyone is having a similar issue:

I found that the {label} tag was not populated completely as I had thought for every UDT. Changing this to {InstanceName} resolved the issue!