Found with PFGW Version 3.7.5

428^8927-8927^428 is 2-PRP! (9.5045s+0.0009s)
428^8927-8927^428 is 3-PRP! (9.7533s+0.0004s)
428^8927-8927^428 is 5-PRP! (9.7339s+0.0003s)
428^8927-8927^428 is 7-PRP! (9.6655s+0.0004s)
428^8927-8927^428 is 11-PRP! (9.7612s+0.0003s)

Primality testing 428^8927-8927^428 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 7, base 6+sqrt(7)
Calling N-1 BLS with factored part 0.08% and helper 0.05% (0.29% proof)
428^8927-8927^428 is Fermat and Lucas PRP! (49.4106s+0.0009s)

To be completed...