How to get rid of underfull boxes in the paragraphed footnotes?

[NiAgio]

Version

reledmac 2021/05/30 v2.38.0

TeX Engine

XeLaTeX

Regression

This is not a newly introduced problem.

Description

Hi! I have been preparing a critical edition of a Greek text with (several) diagrams. I do not use parallel typesetting and as far as I have noticed, the problem is not related to certain packages.

Here follows the description of the problem: For all groups of notes in my edition I use \Xarrangement[X]{paragraph}. The problem is that in some cases I get underfull boxes in the footnotes.

Below, I include photos, in order to make absolutely clear what I mean.

Best regards!

The error

The correct layout

Minimal Working Example

My MWE includes only the content of the preamble.
-->

\documentclass[twoside,12pt]{article}
\usepackage{polyglossia,fontspec,xunicode}

\usepackage{endnotes,etoolbox}

\setmainfont{Times New Roman}

\setmainlanguage{english}
\setotherlanguage[variant=ancient]{greek}

\title{\large{\textbf{Title}}}
\author{\large{\textit{\textbf{Author}}}}
\date{}

\usepackage[a4paper,right=4.25cm,left=4.25cm,top=5.25cm,bottom=5.25cm]{geometry}

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt}
\fancyhead[LE,RO]{\thepage}

\usepackage[draft,noeledsec,noledgroup,series={A,B,C,D}]{reledmac}

\lineation{section}

\linenummargin{outer}

\usepackage{calc}
\usepackage{graphicx}
\usepackage{tikz}

\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\usepackage{mathrsfs}
\usetikzlibrary{arrows}

\Xarrangement[A,B,C,D]{paragraph}

\Xnumberonlyfirstinline[A,B,C,D]
\Xnumberonlyfirstintwolines[A,B,C,D]

\Xinplaceoflemmaseparator{0pt}
\Xafternumber[A]{4pt}
\Xlemmaseparator[A]{}
\Xtxtbeforenotes[A]{\textit{\textbf{M}} }
\setmsdatalabel{}
\Xtxtbeforenotes[B]{\textit{\textbf{C}} }
\Xtxtbeforenotes[C]{\textit{\textbf{F}} }
\Xtxtbeforenotes[D]{\textit{\textbf{D}} }

\Xinplaceofnumber[A,B,C,D]{0em}

\firstlinenum{1} \linenumincrement{2}

\marginparsep1em

\begin{document}
\maketitle
\thispagestyle{empty}

\begin{greek}

\beginnumbering
\pstart
\msdata{\textit{α}FR}Ελληνικό κείμενο.
\pend
\endnumbering

\end{greek}
\end{document}

Workaround

I was not able to find any workaround.