Why stef01 en/fault pin is always 1.4V without thermal protection?

[Ricky20211018]

Hi.

My project adopts stef01 chip  for LED driver,I am meeting an odd phenomenon without thermal protection/overcurrent protection(I think),EN/Fault pin sometime is 1.4V,sometime it works well.It can be recurred when i rest the en/fault pin(efuse_rst=L) with normal temperature---28.5 degree(can i regard it as no thermal protection?) as one of two timing:

1) Time1  --- a short period of time

2) Time2  --- time of duration until reset en/fault pin

It's not always like this.My question:

What can cause the problem?

Thank you,

Ricky

[Ricky20211018]

Normal phenomenon, no design modifications have been made as Time3