Shruthi xt acting strange

Hi just built a shruthi xt and it works but sometimes it goes mad.
Changing cut off affects resonance too…
Resonance knob does nothing.
Sometimes displays env1 sustain and value flickers
Sometimes it’s ok
Then envelope 1 release flickers a value.
Then something else… very random.
Then it will work
And then back to randomness.
Have checked chips are firmly inserted.
Checked solder joints.
Reflashed firmware…
Can anyone help please?