I could not duplicate your result (showing last 3 of 10 tested rips but other results consistent)
All source test files from CUETools 2.1.8 compressed using libFLAC -8
then
flac -8 --force *.flac (using flac.exe 1.3.1)
all ratios are ≥ 1.000
E:\>flac -8 --force E:\test08\*.flac
flac 1.3.1, Copyright (C) 2000-2009 Josh Coalson, 2011-2014 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
01.flac: wrote 38820757 bytes, ratio=1.000
02.flac: wrote 38321296 bytes, ratio=1.000
03.flac: wrote 37511600 bytes, ratio=1.000
04.flac: wrote 27624624 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
05.flac: wrote 31336520 bytes, ratio=1.000
06.flac: wrote 21499974 bytes, ratio=1.000
07.flac: wrote 26099143 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
08.flac: wrote 26090780 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
09.flac: wrote 25965161 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
E:\>flac -8 --force E:\test09\*.flac
flac 1.3.1, Copyright (C) 2000-2009 Josh Coalson, 2011-2014 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
00. (HTOA).flac: wrote 27867 bytes, ratio=0.999
01.flac: wrote 4578024 bytes, ratio=1.000
02.flac: wrote 18047899 bytes, ratio=1.000
03.flac: wrote 20906307 bytes, ratio=1.000
04.flac: wrote 42327147 bytes, ratio=1.000
05.flac: wrote 25447212 bytes, ratio=1.000
06.flac: wrote 43811398 bytes, ratio=1.000
07.flac: wrote 46834980 bytes, ratio=1.000
08.flac: wrote 21281388 bytes, ratio=1.000
09.flac: wrote 23251622 bytes, ratio=1.000
10.flac: wrote 12663375 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
E:\>flac -8 --force E:\test10\*.flac
flac 1.3.1, Copyright (C) 2000-2009 Josh Coalson, 2011-2014 Xiph.Org Foundation
flac comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. Type `flac' for details.
01.flac: wrote 75194955 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
02.flac: wrote 45266060 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).
03.flac: wrote 33099510 bytes, ratio=1.000
04.flac: wrote 29421938 bytes, ratio=1.000
05.flac: wrote 71845318 bytes, ratio=1.000
FAILURE: Compression failed (ratio 1.000, should be < 1.0).
This happens for some files for one or more of the following reasons:
* Recompressing an existing FLAC from a higher to a lower compression setting.
* Insufficient input data (eg, very short files, < 10000 frames).
* The audio data is not compressable (eg a full range white noise signal).