The listed trigger is present in the control file of the package. The trigger is an await trigger, which may not be obvious from its name.
Await triggers place rather strong requirements on dpkg that often lead to trigger cycles due to changes in other packages.
If the package does not need the guarantees that dpkg provides to await triggers, please use the "-noawait" variant of the trigger. This is often the case for packages that use the trigger to compile a form of cache.
If the package does need the guarantees provided by dpkg, then please document the rationale in a comment above the trigger and use the "-await" variant of the trigger to avoid this warning.