The root issue is known and was reported to maintainer.
export/templates/ja_beamer-conference-ornate-20min_(pdf2|pdf[45]).*
export/templates/es_beamer-conference-ornate-20min_pdf4_texF
+# issues with listsof, reported to the maintainer
+# https://www.mail-archive.com/search?l=mid&q=of84gj%24l6b%241%40blaine.gmane.org
+# LyX gives the following terminal message:
+#
+# TextClass.cpp (1385): The layout does not provide a list command for
+# the float `sidebar'. LyX will not be able to produce a float list.
+#
+check_load/templates/acmart
+
# ======================================================================
Sublabel: attic