From my understanding , grinding would for example be someone who doesn't attempt a lesson and submit it but instead does it over and over trying to get it to perfection. For example some people do lesson one over and over again before submitting it trying to get it to look perfectly like the lesson, instead of trying their best and getting what they need to improve on. Of course you should strive for this but in the long run. Each lesson in drawabox teaches a concept and once you understand the concept you have a lot of time to get better at it via the warmups. The warmups are where you try and imrpove on what you have been critiqued or see you need improvement on.

is it simply drawing too many pages on the homework assignments in a attempt to make the drawing look more appealing

I think this might do that yes. It takes a while to realise and although Uncomfortable reiterates it, it soaks in after a while that all the things in drawabox are exercises. For example lesson five is not about drawing animals, its about applying construction, conveying mass, organic forms etc. Animals are used as a tool to those elements.

but specifically attempts to get good at a certain exercise/concept

This I don't know but I do look over my attempts and rewatch videos to catch any concepts I missed the first time. So no I don't think this is grinding, understanding the concepts better is deffintley not grinding. Grinding would be taking months on a single lesson to make it look perfect when you already understand the lesson and what you need to work on. Instead of working on it in warmups you stay on that lesson doing it over and over again until you think its perfect.

Grinding is effectively just doing the same task over and over without any clear, objective end point. "Until I do it better" isn't objective, because it is entirely subject to how we feel about our work. Conversely, doing something a specific number of times, or for a certain number of days/hours, or allowing a third party to decide whether we should go back and do more (which we get by having others critique our work, which while still being subjective is at least not tainted by our own biases) provides us with a clearer point at which we can stop and move on.

here is the answer from my day to day life with draw box:-

for me who has to go to work,

I get up 6am everyday look at draw box website theory for the lesson i have to do along with the video do exercises of that lesson (depending how many and how tough i just do 1 or 2 not more)

then go to work by 10 AM then come by 6:30 pm and then come back and startdoing the exercise finishing entrie homework m in a day and move on.

is it grinding? no. because am not drawing more than twom hours and not rushing but taking my time to do so.

having fun while doing is not equal to doing while trying to finish fast.

so there's my 2 cents.