'-bash: line 1: rescanscsi: command not found' error even though script location is in PATH and other script runs fine from same folder

Question

I'm new to linux, trying to switch over from Windows, and I could really use some help. This is actually my first time using a forum such as this so please forgive any errors I make.

I'm using Linux Mint XFCE 64-bit and I have two scripts located in /usr/local/bin/custom, as can be seen as follows:

dasaint@X1:~$ which load-ssh-keys
/usr/local/bin/custom/load-ssh-keys
dasaint@X1:~$ which rescanscsi
/usr/local/bin/custom/rescanscsi
dasaint@X1:~$ whereis rescanscsi
rescanscsi: /usr/local/bin/custom/rescanscsi
dasaint@X1:~$ whereis load-ssh-keys
load-ssh-keys: /usr/local/bin/custom/load-ssh-keys

/usr/local/bin/custom is in my global path, as has been set in /etc/environment

dasaint@X1:~$ echo $PATH
/home/dasaint/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/local/bin/custom:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

Yet when I run rescanscsi, I get the following error:

dasaint@X1:~$ sudo rescanscsi
sudo: rescanscsi: command not found

The strange thing is, if I run sudo /usr/local/bin/custom/rescanscsi it works just fine.

And if I run the other script, load-ssh-keys, without specifying the absolute path, it also works just fine. The contents of the scripts are:

#! /usr/bin/bash
#
# /usr/local/bin/custom/rescanscsi
#
# ReScan all SCSI/SATA Hosts
#
for SHOST in /sys/class/scsi_host/host*; do
    echo -n "Scanning ${SHOST##*/}..."
    echo "- - -" > ${SHOST}/scan
    echo Done
done

and

#! /usr/bin/bash
#
# Script:       load-ssh-keys.sh
# path:         /usr/local/bin/scripts
# Purpose:      add SSH private keys into ssh-agent
# Dependencies: '/usr/bin/expect'
#               '/usr/bin/ssh-add'
# 
# '/usr/bin' must be included in the system path
#
# SYNOPSIS
# --------
# Reads the passphrase from '~/keypsph' and stores it in the variable, 'PSPH', then
# calls '/usr/bin/expect' to spawn ssh-add to add the SSH private keys into 
# ssh-agent and provide (send) the passphrase for the keys, followed by a <return>.
#
# '/usr/bin/expect'  can be installed with:
#   sudo apt install expect
#
# Guide:    https://stackoverflow.com/questions/13033799/how-to-make-ssh-add-read-passphrase-from-a-file
#
# Initialize a variable to store an exit code of '0'
EXITCODE=0
#
# Check whether the passphrase file, 'keypsph' exists in the user's home directory. 
# If not terminate the script with an appropriate message and error code.
if [ ! -f ~/.ssh/keypsph ]; then
    echo -e "ERROR: Passphrase file not found in $HOME/.ssh\nExiting..."
    exit 1
fi
# Read the passphrase from file, 'keypsph'
PSPH=$(cat ~/.ssh/keypsph)
#
# Call '/usr/bin/expect' to spawn ssh-add to add the SSH private keys to X2 into 
# ssh-agent and provide (send) the passphrase for the keys, followed by a <return>.
expect << EOF
spawn ssh-add "$HOME/.ssh/x1-x2_key"
expect "Enter passphrase for /home/dasaint/.ssh/x1-x2_key:"
send "$PSPH\r"
expect eof
EOF
# Error Handling...
if [[ $EXITCODE != 0 ]]; then
  echo -e "Error adding x1-x2_key to SSH Agent\nExiting..."
  EXITCODE=$?
  exit $EXIITCODE
fi
#
# Read the passphrase from file, 'keypsph'
PSPH=$(cat ~/.ssh/keypsph)
#
# Call '/usr/bin/expect' to spawn ssh-add to add the SSH private keys to X3 into 
# ssh-agent and provide (send) the passphrase for the keys, followed by a <return>.
expect << EOF
spawn ssh-add "$HOME/.ssh/x1-x3_key"
expect "Enter passphrase for /home/dasaint/.ssh/x1-x3_key:"
send "$PSPH\r"
expect eof
EOF
# Error Handling...
if [[ $EXITCODE != 0 ]]; then
  echo -e "Error adding x1-x2_key to SSH Agent\nExiting..."
  EXITCODE=$?
  exit $EXIITCODE
fi
#
# Read the passphrase from file, 'keypsph'
PSPH=$(cat ~/.ssh/keypsph)
#
# Call '/usr/bin/expect' to spawn ssh-add to add the SSH private keys to X4 into 
# ssh-agent and provide (send) the passphrase for the keys, followed by a <return>.
expect << EOF
spawn ssh-add "$HOME/.ssh/x1-x4_key"
expect "Enter passphrase for /home/dasaint/.ssh/x1-x4_key:"
send "$PSPH\r"
expect eof
EOF
# Error Handling...
if [[ $EXITCODE != 0 ]]; then
  echo -e "Error adding x1-x2_key to SSH Agent\nExiting..."
  EXITCODE=$?
  exit $EXIITCODE
fi
#
# Read the passphrase from file, 'keypsph'
PSPH=$(cat ~/.ssh/keypsph)
#
# Call '/usr/bin/expect' to spawn ssh-add to add the SSH private keys to X8 into 
# ssh-agent and provide (send) the passphrase for the keys, followed by a <return>.
expect << EOF
spawn ssh-add "$HOME/.ssh/x1-x8_key"
expect "Enter passphrase for /home/dasaint/.ssh/x1-x8_key:"
send "$PSPH\r"
expect eof
EOF
# Error Handling...
if [[ $EXITCODE != 0 ]]; then
  echo -e "Error adding x1-x2_key to SSH Agent\nExiting..."
  EXITCODE=$?
  exit $EXIITCODE
fi
#
# Exit the script with the appropriate exit code
exit $EXITCODE

I have searched the internet for answers but no one seems to have a comparable issue. I am at my wits end and I could really use some advice.

PS:

If I log in as root using su - and run rescanscsi without the absolute path, it also runs just fine.