Probably just a little high on ppm, not a big deal if it doesn’t continue to get worse.
So use only ph’d water?
For soil grow i would probably give a ph’d watering. Check ppm before going in and collect some runoff to check against.
Looks ok just don’t feed more
When I see this on my plants I see it as a good thing. When caught early; like yours; its telling you to back off the feed. It’s a great learning tool to judge your plants limits, most plants have different nute needs and this will help you keep it just on the edge. When just feeding plain water if its RO or distilled I usually put some silica & cal-mag (don’t need a full dose) in it cuz you can’t PH it correctly with no PPM.