As I already mentioned, Magick.NET-7.0.0.0011 crashes with the same error while converting pdf.
Here are the log information plus dumps with and without heap for v7.0.0.0011 in the single archive: https://yadi.sk/d/NwooPAbDfudkg
Here are the log information plus dumps with and without heap for v7.0.0.0011 in the single archive: https://yadi.sk/d/NwooPAbDfudkg