Google merchant feed works fine with manual upload but throws errors on fetch

Question

I have had the same problem across multiple feeds in Google Merchant Center:

1. I will create a feed file and host it without any access restrictions (accessible by bots).

2. I will set up the fetch feed daily in GMC and this initiates a fetch on the feed.

3. All products fail with this message, "The product data you submitted in your feed does not meet the product data specification, so your products were not approved. Fix and update your feed to display products to customers. To see all issues, go to Diagnostics."

4. Diagnostics shows nothing. No products have been added.

5. So I try the same file using manual upload - and it processes the file without any problems!

Is there a less restrictive set of rules that Google uses when processing manual uploads (the XML code is identical in this case)? Does anyone know what the difference is so I can fix the auto fetch feed with missing data?

Here's a look at a sample product:

<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:g="http://base.google.com/ns/1.0" version="2.0">
<channel>
<title>Google Product Export Data Feed</title>
<description>Products exported for use in Google Product Feed</description>
<item>
  <g:id>1AA10FJ10</g:id>
  <title>Global TTC 1 &amp; 2 Wire Braid Steel Crimp Fitting, 7/8-14 Female JIC 37 deg Flare, -10 Hose, Straight</title>
  <description>Global TTC 1 &amp; 2 Wire Braid Steel Crimp Fitting, 7/8-14 Female JIC 37 deg Flare, -10 Hose, Straight</description>
  <g:google_product_category>Business &amp; Industrial</g:google_product_category>
  <g:product_type>Fluid Conveying &gt; Hose Products &gt; Hose Fittings &gt; Steel &gt; Crimp</g:product_type>
  <link>https://www.example.com/ttc-steel-jic-crimp-fitting-1aa10fj10.html?utm_source=google%26utm_medium=organic%26utm_campaign=organicshopping</link>
  <g:image_link>https://www.example.com/media/catalog/product/a/9/a908ccba4d5d54790369f699be29d88e_resolution_f44a.png</g:image_link>
  <g:additional_image_link>https://www.example.com/media/catalog/product/2/b/2b4c029994e7aa8cdd3af5f280e3c682c1c21813_dwg_aqpttcfj.png</g:additional_image_link>
  <g:condition>new</g:condition>
  <g:availability>in stock</g:availability>
  <g:price>23.51 USD</g:price>
  <g:brand>Example Aeroquip</g:brand>
  <g:mpn>1AA10FJ10</g:mpn>
  <g:gtin/>
  <g:identifier_exists>true</g:identifier_exists>
  <g:item_group_id>group_528</g:item_group_id>
  <g:is_bundle>false</g:is_bundle>
  <g:shipping_weight>0.310000 lbs</g:shipping_weight>
  <g:tax/>
  <g:multipack/>
  <g:unit_pricing_measure> </g:unit_pricing_measure>
  <g:unit_pricing_base_measure> </g:unit_pricing_base_measure>
</item>
</channel>
</rss>

Thanks!