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Description

from #7651:

After a lot of testing I found that in order changes in visibility_timeout value to take effect, one must set it in all, celery config, result backend & transport options, as follows :
visibility_timeout = 600
result_backend_transport_options = broker_transport_options = { 'visibility_timeout': 600 }
So the reported behavior might not be a product defect per se, just lack of proper documentation