When I get to the regulous sector and go on the quest chain to patrol the kassae sector. the very first planet listed (located at the end of the map near dace) where you have to detroy the mining vessels and patrols and scan for radiation (find out its a borg cube) was difficult the first time through. The first time i played it battle cruiser shields were like that of the kassae mission on top of that it literally respawned fighters faster than my CD for the torpedo buff (every minute). also the frieghters or frigates were really tough to kill as well. After dying and going back using a similar the game difficulty returned to normal and things died as they should. At some points i couldnt even fire weapons though energy was plentyful. Even after manually targeting them weapons still didnt fire using the keyboard shortcuts on icon on screen.
Further to this mission chain, today was unable to access Sardah, got to the system and nothing, no join, nothing. So that chain is currently uncompleteable, at least for me, did them in order, skipped when i couldnt complete and went back, still no access to that system.