padding added by croppadd is not black

Using VLC 3.0.2 64bit on Win 10\ Enabling the croppadd filter to add 140 black pixels at the bottom of videos. \ I do get a 140-pixel padding but it does not appear black but dark grey or pink depending on the videos.\

Log:

main debug: using vout display module "direct3d11"
direct3d11 debug: D3D11 pool succeed with 38 surfaces (1792x1152) context 0x0000000008429528
main debug: original format sz 1792x1088, of (0,0), vsz 1792x1080, 4cc DX11, sar 1:1, msk r0x0 g0x0 b0x0
main debug: Adding 'croppadd' as interactive
main debug: looking for video filter module matching "croppadd,chain": 46 candidates
croppadd error: Unknown input chroma DX11
chain debug: Trying to use chroma I420 as middle man
main debug: looking for video converter module matching "any": 24 candidates
main debug: using video converter module "d3d11_filters"
main debug: Filter 'd3d11_filters' (0000000007ca1010) appended to chain
main debug: looking for video filter module matching "croppadd,chain": 46 candidates
croppadd debug: Crop: Top: 0, Bottom: 0, Left: 0, Right: 0
croppadd debug: Padd: Top: 0, Bottom: 140, Left: 0, Right: 0
croppadd debug: 1792x1088 -> 1792x1220
main debug: using video filter module "croppadd"
main debug: Filter 'croppadd' (0000000007ca1380) appended to chain
main debug: using video filter module "chain"
main debug: Filter 'croppadd' (0000000007ca0ca0) appended to chain
main debug: Adding a filter to compensate for format changes