OK
In order for the triple bonus to trip(pull in),the normally closed switch completing the path will open when relay is activated as shown on your snip,but it must complete the double bonus first.
On your snip you see double bonus relay and the sequence of relays that will trip it.
In order for the triple relay to activate you must finish a 2nd set of relays sequence for it to activate to complete its path, thats how it should activate.
This is what happens >>>When the double bonus relay activates through the normally closed switch the make and break within that relay will move which will allow the change of the circuit flow.

When the triple triple bonus relay activates its normally open contact (snip in blue) close allowing the future continuation through the Score motor (3-C cam).

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Seen on the schematic snip>The lower circled red in my snip is the open relays that must close allowing the circuit to the dbl bonus re.allowing m&b to happen seen in the upper red.
The blue circle is N.o. which will close when the triple pulls in.
From what i see you could possibly have a magnetized triple relay armature,remove and tap with a hammer.
Also the triple n.o. contact could be bent closed,adjust if needed.
Find the fault.