For context I am new to OTB chess with 30 games under my belt and a rating of around 1930 fide. I have a very definite problem. Last tournament I dropped 3 pieces in 3 consecutive games in either equal or better positions, 2 of those were free pieces which were being attacked and not defended, one of those is a familiar pattern, discovered Queen attack on the knight on h5 in the king's indian, which I noticed and then forgot about. The other was a free pawn in a somewhat better position (haven't noticed), the third was allowing myself to get forked by a bishop onto my knight and rook so that I must give away one of the pieces in a around +2 ending for me. Yesterday I played a league game against a 2100 fide and had a completely dominant position after 17 moves. Then the familiar pattern occurred, I dropped a pawn, followed by dropping a pawn again. The control I had over the position dissipated, but I managed to complicate and hold a draw.
This problem happens online as well. I either start dropping pieces in a better position or I can't convert +7 positions (not always, but it happens way too often). Similarly, I played against 2 FMs (2200 fide) OTB and had a +7 and +6 lead respectively and still managed to lose the games. A part of the problem is time management, a part is an inherent bias towards controlling the position and not wanting to let go of the control and then losing the edge since the position demands converting.
I don't think I have problems tactically, for reference I am now doing Jacob Aagaard's book "Grandmaster preparation: Calculation". I take about 15-20 minutes approximately for a puzzle and in the first 20 my score is 15.5/20 (0.5 for recognizing the idea, but wrong execution).
When writing this it dawned on me that there are two problems: 1.)dropping pieces for no reason and 2.)failing to convert winning positions.
I was wondering if anyone has/had a similar problems and if so what did you do to ameliorate them/it?