I removed my $HOME/.gscan2pdf file, and that worked around the issue.
Here's my old one for reference.
downsample dpi = 150
default filename = %a %y-%m-%d
selection = 3
selection = 0
selection = 457
selection = 751
auto-open-scan-dialog = 1
libsane-perl version = 0.05
author =
thumb panel = 100
unsharp threshold = 0.05
rotate reverse = 0
scan prefix =
unpaper on scan =
Dark threshold = 0.12
scan-reload-triggers = mode
unsharp radius = 0
scan_window_width = 510
date offset = 0
user_defined_tools = gimp %i
<Paper>
<A4>
t = 0
y = 297
x = 210
l = 0
</A4>
<"US Legal">
t = 0
y = 356
x = 216
l = 0
</"US Legal">
<"US Letter">
t = 0
y = 279
l = 0
x = 216
</"US Letter">
</Paper>
title =
image type = pdf
SANE version = 1.0.24
pages to scan = 0
rotate facing = 0
Paper size = A4
window_height = 811
keywords =
ocr language = eng
<"unpaper options">
no-grayfilter =
layout = single
no-noisefilter =
black-threshold = 0.33
no-blurfilter =
no-deskew =
deskew-scan-direction = left,right
no-mask-scan =
border-margin = 0,0
no-border-align =
output-pages = 1
white-threshold = 0.9
no-border-scan =
no-blackfilter =
</"unpaper options">
unsharp sigma = 1
cache options = 1
window_maximize =
version = 1.3.0
OCR output = replace
window_y = 145
Blank threshold = 0.005
pdf font = /usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf
startup warning = 1
unsharp amount = 1
quality = 75
<profile>
<color>
resolution = 150
</color>
<color>
mode = Color
</color>
</profile>
downsample =
<default-scan-options>
resolution = 150
</default-scan-options>
<default-scan-options>
br-y = 296.993576049805
</default-scan-options>
<default-scan-options>
page-height = 297
</default-scan-options>
<default-scan-options>
page-width = 210
</default-scan-options>
<default-scan-options>
br-x = 210
</default-scan-options>
<default-scan-options>
mode = Color
</default-scan-options>
subject =
<visible-scan-options>
page-height = 1
wait-for-button = 1
l = 1
x = 1
compression = 1
overscan-bottom = 1
page-width = 1
overscan-top = 1
resolution = 1
button-wait = 1
contrast = 1
calibration-cache = 1
mode = 1
threshold = 1
Paper size = 1
pagewidth = 1
adf_mode = 1
y = 1
brightness = 1
source = 1
gain = 1
batch-scan = 1
speed = 1
adf-mode = 1
t = 1
pageheight = 1
</visible-scan-options>
scan_window_height = 596
device = fujitsu:ScanSnap S1500:139678
window_width = 1257
window_x = 664
pdf compression = auto
frontend = libsane-perl
OCR on scan =
threshold tool = 80
Page range = selected
restore window = 1
default profile
layout = single
ocr engine = tesseract
resolution = 150
