Graph API /exportItems request

Hi All,

I use Graph API /exportItems request to read various items from mailbox, then add some custom properties to item and save it to another folder with /createImportSession. To do it I have to parse the returned data based on Bulk Data Transfer Protocol. It worked for EWS call <m:ExportItems> and then also for Graph API. But recently I clashed with case which differs from prev format. I got such binary data for properties

1. 40 40 03 17 00 02 b2 77 f4 a6 e2 42 dd 01
2. 40 40 04 17 00 02 13 40 0d a7 e2 42 dd 01
3. 0b 40 05 17 00 02 00 00
4. 40 40 09 33 00 02 00 4f cb 58 67 3c dd 01

i.e. property type is 0x4040 or 0x400B. If remove this mask 0x4000 then it looks like correct type SystemTime and Bool and next data also looks correctly as SystemTime and Bool values if we skip these 2 bytes 00 02 from every property.

So my question - how should I process such data and what mask 0x4000 means and also what these 2 bytes 00 02 means?

Can some developer explain it because I couldn't find any info.