Shimano free stroke adjustment is basically pointless anyway. Are you 100% sure everything is bled properly? Sometimes a bubble caught behind a piston will be stubborn to move. Try bleeding with the pistons most of the way out, flushing fluid up and down the system a few times (you'll need a syringe at the caliper end rather than a bag as per Shimano instructions) be careful not to pop the pistons out, a bodged thinner bleed block may be useful. Then spread pistons, can push fluid through again for luck, then with the bleed cup on the lever pump it about 50 times whilst tapping the hose to really get everything out, make every 10th pump (ish) a big, long, hard squeeze. Can try the last part first and if it works ignore the first part.
Shimano free stroke adjustment is basically pointless anyway. Are you 100% sure everything is bled properly? Sometimes a bubble caught behind a piston will be stubborn to move. Try bleeding with the pistons most of the way out, flushing fluid up and down the system a few times (you'll need a syringe at the caliper end rather than a bag as per Shimano instructions) be careful not to pop the pistons out, a bodged thinner bleed block may be useful. Then spread pistons, can push fluid through again for luck, then with the bleed cup on the lever pump it about 50 times whilst tapping the hose to really get everything out, make every 10th pump (ish) a big, long, hard squeeze. Can try the last part first and if it works ignore the first part.