On September 14th, 2018, IBM has released DB Group PTF level 23 for IBM i 7.2 (order number: SF99702), and the SAP Support Required PTF List for IBM i 7.2 (II14741) was updated with that information. Afterwards, IBM has seen a few cases where installing these PTFs resulted in a system reference code B900 37FF during the IPL that followed the PTF installation. This happened only when the PTFs were installed on a system that had installed PTFs for the last time more than two years ago and could only be fixed by restoring the operating system.
In the meantime, IBM has provided PTF SI68398 to prevent that problem from happening and released DB Group PTF level 24 for IBM i 7.2, including that PTF. If you already downloaded the DB Group PTF level 23, load level 24 or ensure that you load SI68398 and mark it to be applied during IPL before you execute the next IPL.
So far, the problem has not been reported for IBM i 7.3 with DB Group PTF level 11. Nevertheless, if you want to be on the safe side, make sure that you load and apply DB Group PTF level 12 or SI68399 before the next IPL.
Contact your IBM support organization if you have questions about this issue.