Some other options you can try one by one:
1. set <carddetect>no</carddetect>
2. If it doesn't help remove the line <rate> from your xml.
3. Block everything i.e. sa, ua and ga
4. Turn ga off and sa/ua on
5. put 0963 at the top of your prio
6. another cfg for a card in the lower slot sci0
Code:
<name>Lower Slot</name>
<type>sci</type>
<mhz>536</mhz>
<node>/dev/sci0</node>
<parity>odd</parity>
<reset>normal</reset>
<export>yes</export>
<enabled>yes</enabled>
<blocksa>yes</blocksa>
<blockua>yes</blockua>
<blockga>yes</blockga>
<boxkey>****</boxkey>
<blockC0>Yes</blockC0>
<carddetect>yes</carddetect>