Last year I had a batch of syrup that was by taste and looks just fine. But when you poured it it was snotty. The syrup would leave streamers like hot mozzarella.
It looked fine going through the filter but the next day was different.
What happened to it. was the sap bad.
I made some into sugar and it was tough to do but the sugar is just fine. The rest went to a friend for sugar in his mash and that tasted just fine.