I had some problems with updating to 0.15.4. I saw random errors in my Proxy Software regarding the reading of Batched Packets. A dump of the RakNet output showed that you are overflowing the RakNet Packet length by the given unsinged short.

This results in Packetlengths which are not correct for reading the data. For example:

0x60
0x0 0xf8 // Data length 31
0x2 0x0 0x0
0x1 0x0 0x0
0x0
0xfe 0x6 // MCPE Batch packet
0x0 0x0 0x20 0x19 // 8217 bytes compressed payload
0x78 0xda 0x1d 0x97 0x79 0x3c 0x54 0xed 0xfb 0xc7 0x4b 0xf5 .... (in total 8217 bytes)

This is logical since 8223 * 8 is 65784 which overflows the unsigned short by 249. If you receive the Packet correctly you see 249 / 8 = 31 bytes as packet length coming out of raknet.