String Manipulation in a called bash script

Question

Using Ubuntu 22.04.1 LTS.

I have two scripts (script1.sh and script2.sh).

If I executed either one independently they work properly. If I call script2.sh from script1.sh it errors on a string replacement command in script2.sh. But if I execute script2.sh directly (not called from another script) it works properly. I have removed passing parameters to simplify the example. In the full script, I will pass SrcRoot and DestRoot from script1 to script2.

I am looking for a way to fix this. In my full script, I will not have SrcFullSpec in script1.sh as it is generated inside of the called script (script2.sh), so it is not an option to pass that as a parameter

#!/bin/bash
#script1.sh
SrcRoot=/mnt/media_bulk/movies
DestRoot=/mnt/media_bulk/new-movies-H265
SrcFullSpec="/mnt/media_bulk/movies/subdir 1/American Sniper.m4v"
echo "Sending SrcRoot: $SrcRoot"
echo "Sending DestRoot: $DestRoot"
echo "Sending SrcFullSpec: $SrcFullSpec"
this is the same string manipulation command in script2.sh
it works properly here
echo ""
ReplacePath="${SrcFullSpec/${SrcRoot}/${DestRoot}}"
echo "Replace Path: $ReplacePath"
sh script2.sh

Output from script1.sh

$ ./script1.sh
Sending SrcRoot: /mnt/media_bulk/movies
Sending DestRoot: /mnt/media_bulk/new-movies-H265
Sending SrcFullSpec: /mnt/media_bulk/movies/subdir 1/American Sniper.m4v
Replace Path: /mnt/media_bulk/new-movies-H265/subdir 1/American Sniper.m4v

Executing scritp2.sh

LSrcFullSpec: /mnt/media_bulk/movies/subdir 1/American Sniper.m4v
LSrcRoot: /mnt/media_bulk/movies
LDestRoot: /mnt/media_bulk/new-movies-H265
script2.sh: 18: Bad substitution

Script2.sh source code

#!/bin/bash
#script2.sh
LSrcRoot=/mnt/media_bulk/movies
LDestRoot=/mnt/media_bulk/new-movies-H265
LSrcFullSpec="/mnt/media_bulk/movies/subdir 1/American Sniper.m4v"
echo ""
echo "********************"
echo "Executing scritp2.sh"
echo "********************"
echo ""

echo "LSrcFullSpec: $LSrcFullSpec"
echo "LSrcRoot: $LSrcRoot"
echo "LDestRoot: $LDestRoot"
echo ""
NewPath="${LSrcFullSpec/${LSrcRoot}/${LDestRoot}}"
echo "New Spec: $NewPath"

Output from executing script2.sh by itself

$ ./script2.sh

Executing scritp2.sh

LSrcFullSpec: /mnt/media_bulk/movies/subdir 1/American Sniper.m4v
LSrcRoot: /mnt/media_bulk/movies
LDestRoot: /mnt/media_bulk/new-movies-H265
New Spec: /mnt/media_bulk/new-movies-H265/subdir 1/American Sniper.m4v