Ann: Quarterly Activities/Appendix 4C Cash Flow Report, page-43

The aspect of cash collection lag has been discussed here for years.
Ian discussed it in a video, which I think may have been from last year's AGM if you want to find that for a better overview.
My understanding, there is a long winded process for an invoice to flow through an American utilities payment cycle, hence the cash flow lumpiness.
It would be a non-event if 3DP was not so reliant on just a few large utility customers at this stage of their business development.
The other market sectors (3DP are targeting) are not yet sufficiently mature enough to help smooth out cash flow collection.
Ian