Attribute "Class" in RADIUS accounting

[tyua]

I have controller MSM760 (6.6.0.0-22530) and AP MSM410/MSM430.

I want to use "RADIUS accounting".
I need to attribute "Class" contains the necessary information to me, such as string "tac".

The manual says:

Class
(string)
As defined in RFC 2865. Multiple instances are supported.

The RFC 2865 says:

5.25. Class
Description

This Attribute is available to be sent by the server to the client
in an Access-Accept and SHOULD be sent unmodified by the client to
the accounting server as part of the Accounting-Request packet if
accounting is supported. The client MUST NOT interpret the
attribute locally.

But the default attribute "Class" already contains data unintelligible «70:0d:07:9a:00:00:01:37:00:01:02:00:0a:00:09:21:00:00:00:00:61:0b:6c:5f:0e:7b:db:a9:01:d2:03:5e:46:1e:de:10:00:00:00:00:00:01:dc:83»,
and if I add the attribute "Class" = "tac" on the RADIUS server, I still do not see this "Class" = "tac" in the accounting information.

Why attribute "Class" already contains information and why not add my information?

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