If a class X has the string constructor X(string) then PowerShell may call
this constructor somewhat unexpectedly.
New-Object X or v5+ [X]::new() may create X from literally any input
object. PowerShell simply converts input objects to stings using their
ToString() methods.
This may be handy in interactive scenarios. But in scripts potential mistakes
may be more difficult to discover. If a not suitable input object is used and
the constructor does not fail, e.g. due to input validation, then X may be
created successfully with some unexpected data.
Script Test-1.ps1 shows the issue. X is successfully created
from a presumably wrong object.
PowerShell casting constructs [X] expression may call constructors as well.
If expression -is [X] then PowerShell literally casts the expression type.
If expression -isnot [X] then PowerShell looks for a suitable constructor of
X depending on the expression type. The constructor X(string) may be called
unexpectedly when expression is not a string and arguably more suitable
constructors exist.
Script Test-2.ps1 shows the issue. X is created using the
unexpected constructor, more likely.