Your sample document is plagued with direct formatting which may play a role in the problem.
You also have inconsistent configuration of your table.
- in 
Text Flow, you request Keep with next paragraph
This may be default setting but does not make sense with a multi-page table. The parameter is intended to keep a short table and its caption on the same page. I don’t know which impact it can have in your case. 
- 
Heading 3 request also Keep with next paragraph
Generally speaking, text flow parameters don’t work well in tables. Here, your heading is alone in its cell. So, does this request that the next row be kept in the same page, with cascading effect? It is likely it is ignored but be safe by disabling it. 
- IMHO, the worst factor is your setting in the heading row of your table
You styled with Table Contents + direct formatting to give it a distinct look against contents cell. The “standard” style is Table Heading which “naturally” separates the appearance without the need for direct formatting.
What drew my attention is the fact that your table starts at top of page 2 instead of following the empty paragraph on page one. Apparently you added page break request in the table heading paragraphs, but I can’t get rid of this page break. It is effective because the split-able table starts at top of page 2, but it probably plays nasty tricks depending on local context in the table. 
At some time, I eliminated the spurious page break in the middle of the table but when I reloaded your document (without saving) to replay my modifications, I could not fix again the issue. The putative fix occurred after I replaced your manual table width by Automatic. Unfortunately it did not repeat.
At this stage, my advice would be to fix the page break configuration in the heading row.