Running the following:
pdfcpu val -v <redacted_pdf>

INFO: 2024/01/18 14:20:05 PDF Version 1.5 conforming reader
INFO: 2024/01/18 14:20:05 validating
STATS: 2024/01/18 14:20:05 XRefTable:

HeaderVersion: 1.6
has 1 pages
using object streams
using xref streams
is linearized file
XRefTable:
Size: 399
Root object: (296 0 R)
Info object: (294 0 R)

Stack trace ensues... with complaint about types.Integer -- which appears to be a standard type and maybe should be supported?

Fatal: pdfcpu: validateNameEntry: dict=StructElementDict entry=S invalid type types.Integer
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateNameEntry
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/object.go:691
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateStructElementDictPart1
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/structTree.go:354
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateStructElementDict
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/structTree.go:459
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateStructTreeRootDictEntryKArray
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/structTree.go:487
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateStructTreeRootDictEntryK
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/structTree.go:533
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateStructTreeRootDict
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/structTree.go:621
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateStructTree
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/structTree.go:690
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.validateRootObject
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/xReftable.go:921
github.com/pdfcpu/pdfcpu/pkg/pdfcpu/validate.XRefTable
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/pdfcpu/validate/xReftable.go:44
github.com/pdfcpu/pdfcpu/pkg/api.ValidateContext
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/api/api.go:80
github.com/pdfcpu/pdfcpu/pkg/api.Validate
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/api/validate.go:55
github.com/pdfcpu/pdfcpu/pkg/api.ValidateFile
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/api/validate.go:99
github.com/pdfcpu/pdfcpu/pkg/api.ValidateFiles
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/api/validate.go:122
github.com/pdfcpu/pdfcpu/pkg/cli.Validate
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/cli/cli.go:32
github.com/pdfcpu/pdfcpu/pkg/cli.Process
/go/pkg/mod/github.com/pdfcpu/[email protected]/pkg/cli/process.go:35
main.process
/go/pkg/mod/github.com/pdfcpu/[email protected]/cmd/pdfcpu/process.go:149
main.processValidateCommand
/go/pkg/mod/github.com/pdfcpu/[email protected]/cmd/pdfcpu/process.go:206
main.commandMap.process
/go/pkg/mod/github.com/pdfcpu/[email protected]/cmd/pdfcpu/cmd.go:143
main.main
/go/pkg/mod/github.com/pdfcpu/[email protected]/cmd/pdfcpu/main.go:56

• Your issue is based on the latest commit
  Running @latest 0.6.0 release.

• State your OS and OS version (Debian bullseye)
  Linux 5.15.90.2-microsoft-standard-WSL2 Adding ability to extract text to an io.Reader #1 SMP Fri Jun 2 00:45:15 UTC 2023 x86_64 GNU/Linux

The pdf may be found here:
https://kingcounty.gov/~/media/depts/records-licensing/recorders-office/documents/MLAPPpdf.ashx?la=en

Any ideas on how to fix would be appreciated.