I installed quast version 5.2.0 via bioconda.
Python version is 3.8.13.

f.seek(block_counter * _buffer, os.SEEK_END) throws an error UnsupportedOperation: can't do nonzero end-relative seeks.
The document says In text files (those opened without a b in the mode string), only seeks relative to the beginning of the file are allowed (the exception being seeking to the very file end with seek(0, 2)).

Then, the exception is caught, and all lines are read.

My combined_reference.bed has a header that does not start with "#".

CHROM_A	START_A	END_A	CHROM_B	START_B	END_B	TYPE
Cohaesibacter_sp._ES.047_NZ_LT907844.1	1925068	1925068	Marinobacter_sp._BSs20148_NC_018268.1	35069	35069	BND
Halomonas_chromatireducens_NZ_CP014226.1	497460	497460	Thioclava_nitratireducens_NZ_CP019437.1	2257828	2257828	INV
Halomonas_chromatireducens_NZ_CP014226.1	498759	498759	Thioclava_nitratireducens_NZ_CP019437.1	1865596	1865596	INV

Therefore, the header is tried to be cast into int in (align1 = (int(fs[1]), int(fs[2]), correct_name(fs[0]), fs[6])) and throws an error ValueError: invalid literal for int() with base 10: 'START_A'.