ETA: I'm also a freelancer. Have been freelancing for the last 5 years. Never waited more than 2 months for an invoice so that is some A grade bullshit. The only people I know who have waited that long are those that work with dodgy companies, or very new ones with cash flow issues.
I am also a freelancer since 2015 - I have also never waited more than 90 days for an invoice to be paid. I had one client who was on 60 day invoicing terms so when I billed at the end of the month, it totalled 90 days cycle time, but that's v unusual. My current client pays 3 weeks in arrears (which is swift) - usually it's 30 days post-invoice as standard.
I think in publishing royalties are paid every 6 months so I can understand them coming in in chunks, but for discreet pieces of work such as DKL, Hellmans, I'd assume it was invoice on completion and then whatever the organisation's standard supplier terms are for small businesses.
I also call bullshit.
Also Jack has been working for some time now, so she should be taking a dividend infrequently out of her accrued profits - usual advice is to try to have at least 6 months worth of pay in hand for situations like this where you don't know exactly when your business bank account will receive the money. All of which tells me, she's overspent again.
Anyway, we shall see when we get a look at the next accounts on or around March 2021 for year 2 of 'On a Bootstrap Ltd'.