Bug: run into `maximum number of workers available with current limits`

[mwallschlaeger]

Bug Description

instance run into (expect to restart):

[busyness] 1s average busyness is at 83% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)
[busyness] 1s average busyness is at 100% but we already started maximum number of workers available with current limits (4)