We give the rules as:

<quote>
19.8.4.20 Streamability of xsl:fork

The posture and sweep of xsl:fork are the first of the following that applies:

1. If there are no child xsl:sequence instructions (other than xsl:fallback), then grounded and motionless.

2. If there is a child xsl:for-each-group instruction, then the posture and the sweep of that instruction.

3. If there is a child xsl:sequence instructions whose posture is not grounded, then roaming and free-ranging.

4. Otherwise, the posture is grounded, and the sweep is the widest sweep of the xsl:sequence child instructions.
</quote>

[A] If there is an xsl:for-each-group instruction then rule 1 will always trigger and we never get to rule 2. Simplest fix: put rule 2 before rule 1.

[B] In 19.8.4.19 I suggest changing rule 4 to:

4. If there is an xsl:sort child element <add>and the instruction is not a child of xsl:fork</add>, then roaming and free-ranging.

[B] In 19.8.4.19 there is a typo: "... presence or absence of call on the current-group function".