The part of the sentence "which sometimes becomes" is correct and usable in written English.
You can use this phrase to describe how a certain thing can transform into something else in certain situations. For example, "The caterpillar, which sometimes becomes a butterfly, begins its journey as an egg."
Its most positive quality, however, despite its posturing, is its whimsy, which sometimes becomes genuine earthy charm.
"From such seemingly petty issues, drop by drop, separatism ripens, which sometimes becomes a stronghold for an even more dangerous evil, international terrorism".
She is equipped with her mother's magical bow which sometimes becomes hazardous as she doesn't quite know how to use its magic.
Stone mechanic characteristics or saw blade tool behaviour affect the process performance, which sometimes becomes a maintenance issue.
Consistent with this suggestion, dogs exhibit more excitatory behaviors than wolves, which sometimes becomes an overreaction yielding anxiety, or even obsessive-compulsive disorder, which may be associated with glutamate-related genes (Sampaio et al. 2013).
Administration was through island governments, which sometimes became enmeshed in sectarian rivalries between Roman Catholics and Protestants.
Players in the 1800's often loaded up at local pubs before the games, which sometimes became rowdy displays of male preening.
Part of the problem came from ensuring that teams were checking these kinds of notes or documents on a regular basis, which sometimes became an issue if people weren't sharing the links around as a reminder, Pasquier said.
A reviewer in Choice: Current Reviews for Academic Libraries stated he was "enthusiastic about this book", praising the "personal quality [of] the narrative, which, though, sometimes becomes overly detailed".
They come with their own genetic material, known as mitochondrial DNA, which sometimes can become mutated and defective.
Ischemia, fluid and electrolyte disorders, autonomic neuropathy, anemia, ion disorders caused by the use of diuretics and valvular calcification are the modifying factors, which sometimes also become the triggering ones [ 15, 21, 26, 46, 47].
