Yes, no, maybe.
The Allison was somewhat well adapted in 1942 in the P-38. The Merlin 61 in the Spitfire IX (4 squadrons in Aug 1942?) wasn't doing that much better.
The Allison of 1940 had some problems as a basic engine, it was improved near the end of 1940 (needed new crankcase and new crankshaft).
The P-38s had problems in late 1942/early 1943 using higher powers due to both the radiators and due to the intercoolers.
The P-38 did have a lot of problems but a lot of them were actually somewhat minor. And some of them were poor training, not mechanical problems.
One squadron in India blew up something like 11 left hand engines and only one right hand (or the other way around) before they figured out that the throttle linkage system NOT were mirror images of each other and needed to adjusted differently. This was done by an Allison factory service rep flying behind the pilot with nacelle panels removed for pictures observation. Parts were locally manufactured. reports sent to Allison, Lockheed, and the US army and over 800 linkage parts kits locally manufactured and many sent to the South Pacific.
In this case there was nothing wrong with the basic engine, or the turbo or the intercooler. But it did need to be "fixed".