> If an initial replication attempt failed, the researchers added even more participants.
This is an obvious way to tamper with the results; it's just more of the same kind of p-hacking that bad researchers are so often doing. They are using "we re-do the study with a larger population" as a way to re-roll the dice if the first die roll doesn't come up the way they want. (Note that if the die roll did come up the way they want, they don't re-do the study with a larger population in order to see if the replication fails).
This is an obvious way to tamper with the results; it's just more of the same kind of p-hacking that bad researchers are so often doing. They are using "we re-do the study with a larger population" as a way to re-roll the dice if the first die roll doesn't come up the way they want. (Note that if the die roll did come up the way they want, they don't re-do the study with a larger population in order to see if the replication fails).
Nobody should be taking this seriously.