Event Detail Template No Longer Displays Custom Property


Our client is currently integrated with our app, which uses a custom timeline event with a custom property to display a chat log on a contact’s timeline.

We’ve recently discovered the log is no longer displaying on the timeline, and all previous timeline events now have the custom property ommitted. I’m aware that detail template changes are retroactive, so I’m thinking something changed on the Hubspot side so the template no longer displays our custom property.

The event:

All new and previous timeline events now display only Log:, the property is no longer being printed.

Any help would be appreciated!


Hi @ccrampton,

Can you send me a link to the event template in your developer portal so I can take a look?


Sure thing,



Hi @ccrampton,

Sorry for the back and forth; I also need an example contact in a test or production portal that is experiencing this issue so that I can look at the event data.


No problem at all - https://app.hubspot.com/contacts/3021879/contact/17736751/?interaction=note

Thanks @Derek_Gervais!


Hi @ccrampton,

Thanks for the info. I’ve been digging into this and it appears that this is an issue on our end. I’m going to take this to my team and dig in further. I’ll update here when I have some more information.


Thank you @Derek_Gervais - glad to hear it’s something you can dig into.

Please let me know if/when you find anything.


Hi, @Derek_Gervais.

I wanted to check in to see if you made any progress on this ticket, and have identified the issue? Or, at least can provide an update.

This is currently blocking us on our end.

Thank you,


Hi @ccrampton and @Stephanie_Stevens,

Thank you both for your patience here, and apologies for the delay; this issue was particularly tricky to pin down. It turns out that this is due to the behavior of the underlying library used by the events template renderer, handlebars (see below). {{log}} is actually a token built into Handlebars; it is used to write out a log message. While the backend was able to store values for your custom log property, the front end wasn't able to render the property. Instead, the {{log}} token was writing a handlebars log to our servers. Because log is reserved for use as a built-in handlebars helper function, it cannot function as a property in an event type.

Going forward:

  • All existing values for your log properties exist; the issue only affects the rendering of that property, not the value.
  • If you create a new property with any name other than log and lookup, you'll be able to render it without issue.
    • log and lookup are the only existing Handlebars helpers that have the same format as event property tokens
  • In order to 'fix' existing events, you'll need to copy the value from the existing log property into your newly created event property (maybe chatlog?). You can use the endpoints below to pull the events you have stored externally and update your new property with the existing value for the log property.
  • I'll work on updating the documentation to more explicitly call out the log and lookup reserved values to avoid this issue going forward.



Thank you so much, Derek!