leaving something, in...

[Deinonychus]

Meanwhile, along the Gomel’ axis, in addition to leaving V. I. Kuznetsov’s 3rd Army, with its single reinforced 66th Rifle Corps in semi-isolation west of the Dnepr, the loss of Gomel’ forced roughly half of Gordov’s 21st Army to retreat eastward and southeastward.

Source:Barbarossa Derailed: The Battle for Smolensk 10 July-10 September 1941: Volume 1 by David M. Glantz

Good day, everyone!
Is it acceptable to insert a comma(the one in red) between the verb phrase "leave something in" for native speakers?
Should the phrase underlined be corrected to something like:
"in addition to leaving V. I. Kuznetsov’s 3rd Army, with its single reinforced 66th Rifle Corps, in semi-isolation west of the Dnepr"?

Thanks in advance!

 

[The Newt]

I suspect there should have been commas both after "Army" and after "Corps."

 

[Deinonychus]

I suspect there should have been commas both after "Army" and after "Corps."

Thanks a lot, The Newt!
So can one say that the use of the comma in the original sentence is unacceptable?

 

[The Newt]

Thanks a lot, The Newt!
So can one say that the use of the comma in the original sentence is unacceptable?

The original punctuation makes the sentence harder to follow.

 

[Deinonychus]

Thank you very much for help, The Newt!

 

[PaulQ]

Is it acceptable to insert a comma(the one in red) between the verb phrase "leave something in" for native speakers?

Yes, in fact, it is helpful.

, with its single reinforced 66th Rifle Corps in semi-isolation west of the Dnepr,

Here, the commas indicate parenthesis as the whole phrase is non-defining.