An external text entity is being resolved more than once.
#6144 Run-time catchable error
An external text entity is being resolved more than once.
Additional Information
The event for the external text entity 'X' has already been processed.
Explanation
Every external text entity must be processed and resolved by running exactly one external-text-entity
rule. This error indicates that an external text entity event has been processed more than once. This can happen
if, for example, the parsed markup is directed into multiple markup sink functions, and each of them
performs a do markup-parse on their input.
You can use the function split-external-text-entities to make sure that external text entity events
are directed to only one markup sink.