Memory method node problem in LabVIEW FPGA 2013

Hello everyone in this forum. This is the first time here :) 

I have a problem with reading values from my FPGA block memory. 

In summary, this is bit counter for each word in Huffman tree.

In first times it completes while cycles correctly, but later it starts to read uncorrect values from memory addreses which it has already read several times.

I am new in LV and in LV FPGA. Could someone suggest a solution?

Thanks