What is the meaning of the following: " completion of open rounds of DNA replication"?
From the context of the article I found from an internet search:

Cell cycle exit in bacteria encompass four general steps:
(i) inhibition of inappropriate reinitiation of DNA replication,
(ii) completion of open rounds of DNA replication,
(iii) segregation and compaction of daughter chromosomes, and
(iv) septation.

I would assume that ‘open rounds’ means ‘DNA replication that has already been started’ (‘open’ signifying already started, and a ‘round’ has the sense of one event of a series). ‘Completion’ is obviously ‘finishing’, ‘ending’ — the cell cycle doesn’t end until all the replication that has started has finished.
I have not seen the adjective ‘open’ used in this way previously, and suspect it is uncommon, but as this is not my field I stand to be corrected.