sunshine-thumbnail

When i check with Regenerate Thumbnails.
i see

Thumbnail Sizes
These are all of the thumbnail sizes that are currently registered:

thumbnail: 150×150 pixels (proportionally resized to fit inside dimensions)
medium: 300×300 pixels (proportionally resized to fit inside dimensions)
medium_large: 768×0 pixels (proportionally resized to fit inside dimensions)
large: 1024×1024 pixels (proportionally resized to fit inside dimensions)
1536×1536: 1536×1536 pixels (proportionally resized to fit inside dimensions)
2048×2048: 2048×2048 pixels (proportionally resized to fit inside dimensions)
sunshine-thumbnail: 564×999999 pixels (proportionally resized to fit inside dimensions)
sunshine-lowres: 798×531 pixels (proportionally resized to fit inside dimensions)
free: 600×600 pixels (proportionally resized to fit inside dimensions)
1200-pixels: 1200×1200 pixels (proportionally resized to fit inside dimensions)
1920-pixels: 1920×1920 pixels (proportionally resized to fit inside dimensions)
800-pixels: 840×840 pixels (proportionally resized to fit inside dimensions)
800-pixels-2: 1024×1024 pixels (proportionally resized to fit inside dimensions)

i cant change 999999 in the sunshine Thumbnail Height settings
i have 376 for it, but it ceeps on 999999.