It MAY cause hypoglycaemia. Without seeing any sources we have no way of knowing how frequently that has been reported as a side effect or how it arrived at that conclusion.
Most reports state that raising iron levels if anything have a lowering effect on hb1ac. That’s different to having a hypo though. I’m assuming it’s something along the lines of having more iron in the blood means the glucose load is better “spread” so each cell takes up less glucose thus lowering hb1ac.
Being on iron replacement therapy myself (ferrous sulphate/fumerate pills not gluconate jabs) I’d like to see the sources. Maybe it’s just the gluconate version though. Out of interest where did you get your info about it being converted into glucose?