"Given" versus "Given that"

I just received a proofread version of an academic manuscript from my copy editor. She essentially changed all of the instances in which I had written "given that" to "given." I've tried to read up on the distinction, but I am getting contradictory information. From a reading-aloud perspective, it just does not sound right to me to take out the "that", but that may just be my bias.

For example:

"Given that the CEO had recently resigned, the company had trouble raising its next round of financing."

was changed to

"Given the CEO had recently resigned, the company had trouble raising its next round of financing."

Are "given" and "given that" actually interchangeable? According to the dictionary, they both mean "when you consider something"...

The Cambridge Grammar of the English Language (Huddleston & Pullum, 2002) give a list of adverbs and prepositions that take content clauses as complements (p. 971). The majority of these items do not allow that at the beginning of the content clause - they take non-expandable clauses:

• Though [that the complainants are wealthy], .... (ungrammatical)
• Though [the complainants are wealthy], ....

However, they also list an important subset of prepositions and adverbs which can take expandable content clauses. In the case of these items, the word that is permissible and may often be preferred, but is also optional. Here is an example with the item provided:

• I'll come along, [provided (that) I can leave early]. (p. 971 example (56.ii.a))

The item given (that) is also included in this list. This shows that the Original Poster's [OP's] original examples were perfectly correct and entirely grammatical.

There are three possibilities with regard to the editor's interference here. Firstly, they may be unaware that given can take expanded clauses with that - possible, but maybe unlikely. A second is that they feel that it's better style in many of the OP's cases not to use that. A third possibility is that they are just trying to save space, ink and money.

I agree with the OP that their particular examples sound better with that included. But that's taste for you; it rarely has much to do with grammaticality. It seems to me that the editor has some explaining to do here.

^{The Cambridge Grammar analyses many items that traditional grammars take to be subordinating conjunctions as prepositions. Nothing at all hinges on this.}