A website called knucklerap reported on a collaborative grammatical/editing discussion on Metafilter (although the knucklerap writer mistook one participant in the thread for the owner of the site). Part of the cited discussion:
“The problem is that the conjunction ‘as well as’ introduces a compound object phrase which is not parallel. Either both verbs [serve and witness] ought to be gerunds, or both ought to be infinitives.”
The phrase “in turn” attracted scrutiny, and for good reason. “Riviera” pointed out that it causes “temporal confusion, because you begin with the idea of the sequential (‘in turn’) and go to parallelism (‘as well as’).”