Uncorrectable medium error in 3 drives of the LSI-9260-16i RAID5 system

We have a storage machine (file server) with a LSI Megaraid 9260-16i RAID system, and 15 hard drives configured as RAID5 plus one spared hard drive. Each hard drive is a 4TB SATA3 disk. Recently we found the following the same "Patrol Read" error event logs happened in 3 of the hard drives in the RAID5:

Code: 0x0000005f
Class: 3
Locale: 0x02
Event Description: Patrol Read found an uncorrectable medium error on PD 1b(e0xf5/s15) at e0377d38
Event Data:
Device ID: 27
Enclosure Index: 245
Slot Number: 15
LBA: 3761732920

Code: 0x0000005f
Class: 3
Locale: 0x02
Event Description: Patrol Read found an uncorrectable medium error on PD 11(e0xf5/s5) at e0377d38
Event Data:
Device ID: 17
Enclosure Index: 245
Slot Number: 5
LBA: 3761732920

Code: 0x0000005f
Class: 3
Locale: 0x02
Event Description: Patrol Read found an uncorrectable medium error on PD 15(e0xf5/s12) at e0377d38
Event Data:
Device ID: 21
Enclosure Index: 245
Slot Number: 12
LBA: 3761732920

It is quite strange that the uncorrectable medium error appeared exactly at the same address e0377d38 in three hard drives (e0xf5/s15), (e0xf5/s5), and (e0xf5/s12). It caused the RAID card automatically start background initialization again and again. From the event log it seems that the RAID card tried to fix this error, but always failed.

We are not quite sure why this problem was raised. Recently we replaced two of the above three hard disks, i.e., (e0xf5/s5) and (e0xf5/s12), due to the original disks broken about 3 weeks ago. It seems that after the hard disk replacing the problem came up.

Could anyone suggest me how to fix this problem ? and what's the consequence in case that it cannot be fixed ?

Thank you very much for your kindly help.

T.H.Hsieh