Sweet scotch?

[livwire68]

A couple months back I bought a bottle of scotch, dont remember what type. The first couple glasses were fine then a few days later I tried it again except it was sickly sweet. I asked everyone in the house if they messed with it and no one had so I tossed the bottle. A couple weeks back I bought some bowmore islay single malt to try and it has been fine until tonight. I poured the last glass and as I sit here and drink it, it also seems sweet, not near as sweet as the other, but like if I let it set a couple more days it would become scotch syrup. Anyone else ever have this problem or is it just me.