I feel this should be an option (toggle) on Last Modified Time fields. Like “Modify time when lookup fields change”. Something like that.
How does it work right now? Currently when a lookup field changes, last modified time fields don’t change on the linked record. This makes sense since you’re not actually changing the record.
How would this be even better? Add a toggle to also update LMT fields when lookup fields change. There are use cases with automations and above all syncing and updating with zapier that you could want to trigger a modified field.
There are workarounds on this. I usually do it with automations in airtable. For example bringing the Last modified time from the linked record as a lookup field, and then using a function with DATETIME_DIFF to check for differences. Whenever there’s a difference, you trigger a small change on any of the other cells. But that seems overkill (three new cells just to perform this check). I think a toggle would solve a lot and be a lot cleaner.