IPA / RHDS - Getting "Protocol error" when running some commands.

Issue

With some versions of the 389-ds package:

• Requesting an empty attribute fails with the error message "Protocol error":

# rpm -qa | grep 389-ds
389-ds-base-1.3.7.5-29.el7_5.x86_64
389-ds-base-libs-1.3.7.5-29.el7_5.x86_64
#

# ldapsearch -xLLL -D "cn=Directory Manager" -W -b cn=config -sbase objectclass=* ""
Enter LDAP Password:
Protocol error (2)
#

• There are failures when running some IPA commands:

# ipa user-show admin
ipa: ERROR: Protocol error: 
#