Just a thought: did you dissolve sodium hydroxide and borax together, separately from the rest, before adding that solution to the solution already containing Metol and Ascorbic Acid, or did you add hydroxide as the 3rd ingredient, that is straight after ascorbic acid? I wonder if this could have an impact, perhaps a resident chemist would weigh in.

PS. I believe you would get significant all-over chemical fog if the developer were so out of balance, that the restrainer would not do its job.