Disk could not be partitioned

Bought new iMac 2017 with 1tb FusionDrive, did my own fusion drive from external ssd and internal ssd. Now I try to install windows on 1TB HDD. But all the time when I run Boot Camp and it wants to create a partition, I get the "Your disk could not be partitioned" error.

Here is the overview of my drive:

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 28.0 GB disk0

1: Apple_CoreStorage Fusion 27.6 GB disk0s1

2: Apple_Boot Boot OS X 134.2 MB disk0s2

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_HFS Emptied 883.0 GB disk1s2

3: Microsoft Basic Data OSXRESERVED 8.0 GB disk1s3

4: Microsoft Basic Data BOOTCAMP 108.9 GB disk1s4

/dev/disk2 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: CCCOMA_X64FRE_PL-PL... +4.6 GB disk2

/dev/disk3 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *512.1 GB disk3

1: EFI EFI 209.7 MB disk3s1

2: Apple_CoreStorage Fusion 510.6 GB disk3s2

3: Apple_Boot Recovery HD 650.0 MB disk3s3

/dev/disk4 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +532.8 GB disk4

Logical Volume on disk0s1, disk3s2

F7F891C0-9A1A-48CE-9305-3C1AAC9EF274

Unencrypted Fusion Drive