ASN.1 hex decode

[AK47-2020]

Describe the bug
This string
311A
3009
0603
550406
1302
554B
310d
300b
0603
55040A
0C04
47434851

decodes as
SET
SEQUENCE
ObjectIdentifier countryName (2 5 4 6)
PrintableString 'UK'
SET
SEQUENCE
ObjectIdentifier organizationName (2 5 4 10)
UNKNOWN(12) 47434851

Line before last, change 0C04 to 0c04

The sequence now decodes as

SET
SEQUENCE
ObjectIdentifier countryName (2 5 4 6)
PrintableString 'UK'
SET
SEQUENCE
ObjectIdentifier organizationName (2 5 4 10)
UTF8String 'GCHQ'

To Reproduce
Steps to reproduce the behaviour or a link to the recipe / input used to cause the bug:

1. Go to https://gchq.github.io/CyberChef/#recipe=Parse_ASN.1_hex_string(0,32)&input=MzExQQozMDA5CjA2MDMKNTUwNDA2CjEzMDIKNTU0QgozMTBkCjMwMGIKMDYwMwo1NTA0MGEKMEMwNAo0NzQz

Expected behaviour
Is the ASN.1 module only supporting capital letters for lengths in hex?

Cheers,

AK