Running FT8 or CW without a band cable is not a good idea. The reason is that for both modes, the waveforms rise to full power out in less than 6ms. The LA-1K takes between 20ms to do the band selection. During that 14 ms time period, your transceiver is seeing something close to an open circuit, and the relays in the LA-1K hot switch with full drive power. Not good on either your rig or the LA-1K relays. SSB does not have the rapid rise time, so the problem is a little less serious. My website may help explain this a little more.
GL
.... Bill K3HZP
Bill K3HZP