Leonardo Spectrum - preserve_signal attribute

[Kenneth Le]

I have added preserve_signal attributes to some signals in the VHDL
source codes, and got the following warning messages in Leornado :

WARNING: The value of an attribute is being overwritten:
WARNING: On object named: clk
WARNING: Attribute name: preserve_signal
WARNING: Old Value: true
WARNING: New Value: <NOT SET>

These warnings do not apply to all preserve_signal attribute signals.
Do you know what may have caused these warnings to appear ?

Thanks.

Kenneth