Weird characters in universal persistence output

We're using Exchange 2010, and we've followed the implementation guide. As such, we're using universal persistence for activesync. This part of the iRule from the implentation guide sets this:

 } elseif { [HTTP::header exists "Authorization"] && [string tolower [HTTP::header "Authorization"]] starts_with "basic" } {
 set as_key [sha256 [HTTP::header "Authorization"]]
 persist uie $as_key 7200

When I query the persistence table from the CLI I see a lot of universal persistence records, but they have a lot of weird characters (inclusing line breaks and such). My question: is that supposed to happen? I would have expected a more alphanumeric output. We're running 11.5.3HF1, we've seen this on earlier releases as well.

universal  GôÅèiú~vrÎÄ/5à▒<�å�R�:pÝ��ê=     10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 0)
universal  �5W¿hMßØÿfÑþÔ_ªØE%~lOúHä\=¶
        10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 0)
*'ö¼Ö�t-YÆÚ�ÜÒTCÈmÓOcö[  10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)
universal  �e~�Ò�f¥�▒:£Gy¹­�d¸S½»9eÁ�=~  10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)
universal   úõx£:![$VÉ~Ó&�ç�yÏ�û�EF&ÄÈ«E        10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 0)
universal  "·áòо�¼´5~y³:å�³T÷qIÎ�zný�Û±·�x  10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 0)
universal       ýÌÿ^�Ô$I­Q�OÂïh�Õà/ô4l|³e'Â        10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 0)
universal  Ä?Â/G°Hõ�^5ÂßÍ�Ññ�úÁg¸&Ióü  10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 0)
universal  �`Ä©�)6VÊ Ý¨�á{pðRtsô ùyì   10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)
universal  [�S,.Alõ(�YæV)¡ÐÌ�U3¹uÄíi§£Pp      10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)
universal  Ü�¹
              ÇFcû,�~ubE&üçcæÛa▒Q x
�,      10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)
universal  �¯¡«gá�+9H°'â¤ÏþM³êgð�Vq   10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)
universal  xô�«hû¼Æ:�Ï�¦xtb�ÒSî �     U\` ±��  10.10.88.46%20:443  10.10.129.25%20:443  (tmm: 1)