Problem: The CPU resource demand increases

[MarkowEduard]

If tetris is put into sleep mode with the pause command it starts to increase its demand of the CPU resource. After a few days pausing it consumes currently more than 25 parts of 100 on a 8 core CPU (i.e. 255.99%). Top shows

last pid: 18889;  load averages:  6.47,  6.29,  6.66                   up 330+11:44:16 13:34:35
470 processes: 2 running, 467 sleeping, 1 waiting
CPU: 44.6% user,  0.0% nice,  1.7% system,  0.1% interrupt, 53.5% idle
Mem: 7322M Active, 7881M Inact, 6698M Laundry, 8742M Wired, 502M Buf, 1170M Free
ARC: 3830M Total, 2307M MFU, 832M MRU, 800K Anon, 74M Header, 617M Other
     1725M Compressed, 5208M Uncompressed, 3.02:1 Ratio
Swap: 64G Total, 38G Used, 26G Free, 58% Inuse

  PID USERNAME    THR PRI NICE   SIZE    RES STATE    C   TIME    WCPU COMMAND
   11 root          8 155 ki31     0B   128K CPU0     0    ??? 428.23% idle
12283 xxxxxx       20  20    0   881M   801M uwait    3 153.3H 255.99% tetris
88553 yyyyyy        6  20    0   246M   124M uwait    5  91.4H  87.21% ghc-9.4.6

What's going on there? When put into sleep mode it starts with consuming only very little (1.12%) of the CPU resource: 18900 zzzzzz 20 20 0 121M 26M uwait 4 0:00 1.12% tetris