No, it's not a problem. A host that does this is just treating the
plugin as a 1.1 version and ignoring the extra fields of the struct,
which is completely legal and causes no problems whatsoever.
Besides, the ladspa.h file states:
"""The plugin descriptor from which this instantiate function was
found must also be passed."""
when describing the instantiate() method of the plugin, the only one
that takes a descriptor pointer as an argument, effectively precluding
the plugin code stumbling across the use of a copied descriptor struct
as you describe it.
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