Bug report: PBKDF2-same output for different inputs

[expierd]

When I use the salt same outputs occures for different inputs.
Link to reproduce:
https://gchq.github.io/CyberChef/#recipe=Fork('%5C%5Cn','%5C%5Cn',false)Derive_PBKDF2_key(%7B'option':'UTF8','string':''%7D,128,1,'SHA1',%7B'option':'UTF8','string':'anysalt'%7D)&input=aW5wdXQxCmlucHV0MgppbnB1dDM

Without salt they are different.
I'm using it in Firefox browser on Win10.

[Blank0120]

The input here is not used in this PBKDF2 Operations, cause the five ingredients are the args of pbkdf2.