Okay, so I take the DHL livery for example, since that is the one I noticed the issue with at first.

The specific lievery is, as it is named in ACE, 757-200PCF PCF DHL G-BMRH.
When I want to download this livery from the ACE client, it installs with the Rolls Royce RB211-535E4B engine(in ACE it is shortened to RB535E4B, see Attechments).

If I look up this registration on Airliners.net it will show up the DHL livery with a Rolls Royce RB211-535C engine(in ACE it is shortened to RB535C, see Attechments).

When I go to the local tab, I can select the liveries I have installed. In this case the livery mentioned above.

When I select it, it gives me the option to switch the engine variant. Here is where I get the error because when I want to select either the RB535C engine variant or the RB535E4 engine variant, INSTEAD of the RB535E4B engine variant, I get an error that says the following:

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Something went wrong...
Press Ctrl+C to copy this message and report error:
value: ac_all_ui_type
mid: 804
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OK   
---------------------------

Saving after closing the error only brings up the error up a few more times and than saying the following:

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'' is not found in your simulator.
Make sure '' is installed. (e3)
---------------------------
OK   
---------------------------

But if I were to download the 757-200SF FedEx livery, that installs with the RB535E4 engine variant, and I change the engine variant to either the RB535C or RB5354B engine variant and try to save it, the error does not pop up and the plane loads up with the selected engine variant that I want to use one it.
The same goes for all the Pratt & Whitney engine varients. No error popping up.

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