Ah, looks like the timeout was added in LMS 3.0. The code in LMS uses a static timeout. However, looking at the code, SSHv2 is explicitly not supported in LMS 2.6. The code looks to see that the device replies with SSH-1.5 or SSH-1.99. If the device replies with pure SSHv2 (i.e. SSH-2.0), then the code throws an unsupported version error.
In any event, a better way to test connectivity in any version of LMS is to use RME's Device Credential Verification feature. Go to RME > Devices > Device Management > Device Credential Verification Jobs, and create a new job to test SSH. RME does support SSHv2.