Can we consider the possibility/likelihood that there is nothing wrong?
It strikes me that the idea of equalising is to remove sulphation from the plates, thus increasing the battery capacity, and one would expect the amps drawn to increase at the moment the capacity increase.
My understanding of what ideally happens whilst equalising a sulphated battery is as follows, (based upon Sterlings description in my Pro Combi Charger Inverter manual:
Page 3 "What to expect on this cycle. https://cdn.shopify.com/s/files/1/0658/7343/files/Combi_Q_S_fitting_instructions_USA_EURO.pdf?484
Once the bank is fully charged, i.e. drawing only its tail current, increase the voltage to the equalisation level, (on my charger this is 15.5V), and the amps drawn should increase, but not by much.
Ideally, after a few hours, if/when a chunk of the sulphation is "blown off the plates and back into the electrolyte solution, the capacity of the bank will increase, the voltage will fall and the amps drawn will increase.
Sterling says that it's possible that the voltage could fall to around 12.5V and, if something like this happens, you should revert to normal charging setting until the batteries are fully charged to their recovered capacity.
So... in Tom and Bex case, it seems to me that their equalising may be working perfectly. I dont think they mention the voltage when the amps drawn increases to the 35A or so. It would be interesting to see whether the voltage remains at 15.5V when the amps increase to 35A, or does it fall, even if not as low as 12.5V.