Table &1 is translation relevant but the text flag is not set.

What causes this issue?

The technical settings of table <(>&<)>V1& defines the table as
'relevant for translation'. But none of the existing language fields of
type 'LANG' has the 'Text Language attribute' set.

System Response

With its current definition, the table <(>&<)>V1& is converted to
Unicode with the system code page. Text data not belonging to the system
code page might be converted wrongly.

How to fix this error?

Check the contents of the affected table in transaction SE16. Text data
which have a different encoding than the system code page likely contain
specific Latin-1 characters such as German umlauts. No further action is
required if you cannot find such data.
If Latin-1 data exists you can set the 'Text Language attribute' for the
corresponding language field. After activation of the table, repeat the
SPUMG Consistency Check for the table. The table contents is then
converted according to the contents the language field instead of the
system codepage.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.