The IRS has issued Interim Guidance, dated April 5, 2017, which appears to signal relief and a return to prior practices.
The Interim Guidance is available using the link here. https://www.irs.gov/pub/foia/ig/spder/sbse_05_0417_0011.pdf
This memorandum provides Interim Guidance (IG) for Specialty Collection Advisory and Specialty Examination Estate & Gift Tax employees with respect to all applications for requests of discharge of the estate tax lien made after June 2016.
Hat Tip to Gilbert Hoffman.