destination with the same identifier

Recently compilation in pdflatex introduced new error

destination with the same identifier (...) has been already used

This error has nothing to repeated labels, because compiler reports repeated
labels in the beginning of log. I made some changes in text that I saw on
internet. But they do not help. The text compiles properly. However problem
with this error is that when I compile large text I cannot see real errors.

I will appreciate any help. Thank you

Aleks Kleyn