Would this cause the salt issue?
Typically, insufficient Slow Rinse time.
On many systems, the Brine Draw cycle will be programmed for 60-minutes duration. During the start of that 60-minutes, the brine will be transferred from the brine tank to the resin tank within approx 15-minutes at which point, the air check valve will close to prevent air from being drawn during the remaining Slow Rinse cycle. For the remaining ~45-minutes, slow rinse flow will continue to push the brine through the resin whereby calcium, magnesium, chloride and excess sodium ions will be released and flushed to drain. When the slow rinse time is too short, then the soft water directly following regeneration, will usually taste salty.
As the injector functions as a Venturi, the water flow through the center of the injector, creates a vacuum on the brine port to draw brine from the brine tank. If the injector is dirty, then the rate of brine draw maybe reduced or may not occur whatsoever.
Did cleaning the injector improve operation? Suggest performing a manual regeneration while you are available to monitor each regeneration stage, to ensure brine is fully drawn from the brine tank
You didn't mention any concern with too much brine, but if there is a greater amount than usual within the brine tank, suggest removing out the softener's electrical plug during the brine draw cycle so as to temporarily extend the draw time to ensure all of the brine is drawn out. After all of the brine has been drawn, wait a further 30-minutes before restoring electrical power to provide some additional Slow Rinse time in addition to the Slow Rinse which will continue to occur once power is restored.