I'm assuming this is just a matter of available space but it seems you could get 4 across all aligned but maybe there is another reason. The image is from McGuire AFB but I've seen this on other AFBs.
McGuire AFB being an Air Mobility Command (AMC) base, accounts for the very large C-5 Galaxy when it visits. It may not seem like it, but the 68 m (220 ft) wide C-5 when parked at a 45-degree angle saves ~20 m (65 ft) -- approx. one-third of its wingspan.
The reference used by the USAF is AFMAN 32-1084 (PDF), from which:
184.108.40.206.1. Parking Dimensions. Table 2.9 presents the minimum geometric criteria for fixed-wing apron design. When designing new aprons for AMC bases hosting C- 5, C-17, KC-10, and KC-135 aircraft, provide 15.3 m (50 ft) of wingtip separation.
EXCEPTION: When you are rehabilitating an existing apron, provide the maximum wingtip separation the existing apron size allows (up to 15.3 m [50 ft] but not less than 7.7 m [25 ft]). This additional separation is both desirable and permitted.
By applying that to the C-5 and adding the clearance to the taxiway, those angled spots are a perfect fit:
The measurement above (~83 m) shows two half-span C-5s (68 m) plus the clearance (15.3 m), with superimposed C-5s via pinterest.com
For the other examples you've stated in a comment: Beale AFB and Albuquerque Airport, Tinker AFB, and March AFB -- in that order:
(All imagery is via Google Earth)