I got a copper blank with repeated impressions from Richard Long about 10-12 years ago. Mine is a counterfeiters test blank.
I read the article on multiple resellos and I THINK (my Spanish is very rudimentary) it says that there are at present versions known with 3,4,5 and 8 repeats of the same stamp. They are scarce and there are a variety of reasons postulated. There are NO absolute conclusions.
I get confused about the descriptions used at some points about authorizations because the Spanish is strange (like old English I guess) it seems that multiple stamps could make the coin worth more than one stamp. Each application of a duplicate stamp added to the others? I had never heard of that before. They were cautious to say it did not apply to restamping previously stamped pieces to re-value them a second time. The newer stamp in that case is placed OVER the earlier stamp being done away with.
So they sorted out the examples that were underweight in terms of copper content and indicated they were probably forgeries - some of the period. Some of the exemplars were in collections in the late 17th century.
They also indicate that OVERLAPING identical punches are fakes. In the case of the multiple identical stamps there are not any underpunches present. There is a caution about the host coin being able to be identified. There is some suspicion that counterfeit multiple applicatiosnwere used to obscure the host to allow an illegal coin to pass.
The idea of a test blank used to train mint employees was advanced but no firm conclusions were made there either.
They also indicated that the stamps could not be crude and must meet mint standards - counterfeits both old and new were known to exist.
The total number of examples studied (all from major collections) was few in number and they are approaching these as a VERY rare class in total.
Your example looks great - old - the stamps do not overlap and they ared well done.
One final caution they had one example they think was fake by virtue of the date and mint combination used. Some date mint combinations were not made. But I did not pick up where you can find such a list of which dates were used.