Writing several big matrices in the same file using fwrite

Hello everyone. I need to create binary file with metadata in the first 64kb and matrices sequence (images) starting right after this 64kb. Usually i'l do it like

fseek(fileWriteId,0+32*1024,-1 );

fwrite(fileWriteId,sizeTLSI , 'uint64');
fwrite(fileWriteId,sizeX , 'uint64');
fwrite(fileWriteId,sizeY , 'uint64');
fwrite(fileWriteId,sampling*sizeBuffer , 'uint64');

fseek(fileWriteId, 0+64*1024,-1 );
fwrite(fileWriteId,frame1, 'uint16');
...
fwrite(fileWriteId,frameN, 'uint16');

Where frame - one (or two, it doesn't actually matter) dimensional array. Usually it works fine everywhere, however in matlab i found very strange thing: Namely it works when length of frame is quite small (around several thousands), but if i increase frame length (1280*1024 for example) - it overwriting meta data which i've put into first 64kb.

Anyone know what is wrong with me/Matlab? Or is there some kind of logic behind it?

Tested with Matlab 64x 2014b and 2013b

Test code:

clear all

%A=uint16(zeros(1,10000))+1; %work
A=uint16(zeros(1,100000))+1; %do not work
fileWriteId = fopen('tmp.mlf', 'w');

fseek(fileWriteId,0+32*1024,-1 );
fwrite(fileWriteId,5 , 'uint64');
fwrite(fileWriteId,1024 , 'uint64');
fwrite(fileWriteId,1280 , 'uint64');
fwrite(fileWriteId,1000 , 'uint64');

fseek(fileWriteId,0+64*1024,-1 );
fwrite(fileWriteId,A, 'uint16');
fclose(fileWriteId);

fileReadId = fopen('tmp.mlf', 'r');
fseek(fileReadId,0+32*1024,-1 );
tSize=fread(fileReadId,1,'*uint64')
xSize=fread(fileReadId,1,'*uint64')
ySize=fread(fileReadId,1,'*uint64')
tms=fread(fileReadId,1,'*uint64')
fclose(fileReadId);

Hope to get some answer :)