Bitwise operators should have operands of same type. If not, one or both will be converted before the operation is performed. This is not necessarily a problem but the issue can be helpful if you prefer to be strict about disallowing implicit conversions.
module fly; logic [7:0] a; logic [11:1] b; initial a = a | b; // Noncompliant endmodule
module fly; logic [7:0] a; logic [7:0] b; initial a = a | b; // Compliant endmodule