Why are my AMPScript variables rendering in send preview, but not in test send?

Question

I have a series of AMPScript variables and statements, that are resolving perfectly fine in the send preview.

Once the test is sent out, some of these variables do not resolve and some of them do.

Is anyone aware of a situation in which only some variables would render pre-send, but fail upon send?

Spcifically, the hero image (@heroImgPath), hero link (@heroImgLink), and extra T&Cs (@ExtraTandCs) are not rendering.

Edited to add AMPScript: Edit 2 - reduced AMPScript to just one relevant example

/* Hero image variables */
/* Cars */
VAR @heroImgAdam

/* Other variables */
VAR @HeroImgPath, @HeroImgLink, @HeroImgAlt, @IntroHeadingCopy, @ExtraTandCs, @TandCsCopy1, @TandCsCopy2, @TandCsCopy3

/* Set variable values */
SET @heroImgAdam         = 'http://image.contactvauxhall.co.uk/lib/fe3b15707564077d761178/m/1/9fcbccf1-cf6e-49d4-a155-d77d2b184104.jpg'

SET @HeroImgLinkAdam       = 'https://www.vauxhall-accessories.com/vauxhall-adam-accessories'

SET @HeroImgAlt = 'Accessorise all areas'

SET @IntroHeadingCopy = 'Accessorise all areas'

SET @TandCsCopy1  = 'Please include your registration number and a contact number in your email to help us handle your enquiry efficiently.'
SET @TandCsCopy2  = '<strong>*Service Club Exclusions Terms and Conditions</strong>'
SET @TandCsCopy3  = 'Service Club servicing &amp; repairs discounts; 15% for vehicles 2-3 years, 25% for vehicles 3 years plus. 15% off Genuine and Vauxhall approved Accessories and Parts only – excluding fitting. Online purchases subject to Partsworld Limited T/A Vauxhall Accessories general Terms and Conditions. Half-price MOT test (UK mainland only – excluding Northern Ireland). Free pre-MOT test inspection for customers in Northern Ireland only. Fixed price AdBlue refills; £14.99 for Cars and £24.99 for Vans. Members are entitled to discount on labour and only genuine Vauxhall parts. Parts only purchases excluded. Go to https://www.vauxhall.co.uk/owners/maintenance-and-repair/service-exclusions.html to see full Vauxhall Service Club exclusions. Not valid in conjunction with any other offer. Offers apply to genuine Vauxhall service, MOT and repair work on your UK registered Vauxhall at participating Retailers only. Vauxhall Motors Ltd reserves the right to modify the terms of this promotion at Vauxhall’s discretion at any time.'

/* Set variables for hero image and link */
IF [Creative Model] == 'ADAM' THEN
 SET @HeroImgPath = @heroImgAdam
 SET @HeroImgLink = @HeroImgLinkAdam
ELSE
 SET @HeroImgPath = @heroImgVauxhall
 SET @HeroImgLink = @heroImgLinkVauxhall
ENDIF

/* If there are extra T&Cs, add extra paragraphs to contain them. */
IF NOT EMPTY(@TandCsCopy1) THEN
 SET @ExtraTandCs = Concat('<p style="margin:0px 0px 22px 0px; font-family: Arial, Helvetica, sans-serif, ', Char(39), 'vauxhall-regular', Char(39), '; font-size:12px; line-height:15px; color:#1D1D1B; text-align:left;">',@TandCsCopy1,'</p>')
ENDIF

IF NOT EMPTY(@TandCsCopy2) THEN
 SET @ExtraTandCs = Concat(@ExtraTandCs,'<p style="margin:0px 0px 22px 0px; font-family: Arial, Helvetica, sans-serif, ', Char(39), 'vauxhall-regular', Char(39), '; font-size:12px; line-height:15px; color:#1D1D1B; text-align:left;">',@TandCsCopy2,'</p>')
ENDIF

IF NOT EMPTY(@TandCsCopy3) THEN
 SET @ExtraTandCs = Concat(@ExtraTandCs,'<p style="margin:0px 0px 22px 0px; font-family: Arial, Helvetica, sans-serif, ', Char(39), 'vauxhall-regular', Char(39), '; font-size:12px; line-height:15px; color:#1D1D1B; text-align:left;">',@TandCsCopy3,'</p>')
ENDIF

]%%````

Answer 1

Sometimes Test Sends just fail to render some AMPscript from time to time. Try creating a DE with just your subscriber information and dummy data and send to this DE as a real send.

Before you do the above, also try wrapping your TandCs SET variables TandCsCopy3 in double quote marks. This is because some of the contents of the copy contain single quotation marks (eg: 's)

SET TandCsCopy3 = "Service Club servicing & repairs discounts; 15% for vehicles 2-3 years, 25% for vehicles 3 years plus. 15% off Genuine and Vauxhall approved Accessories and Parts only – excluding fitting. Online purchases subject to Partsworld Limited T/A Vauxhall Accessories general Terms and Conditions. Half-price MOT test (UK mainland only – excluding Northern Ireland). Free pre-MOT test inspection for customers in Northern Ireland only. Fixed price AdBlue refills; £14.99 for Cars and £24.99 for Vans. Members are entitled to discount on labour and only genuine Vauxhall parts. Parts only purchases excluded. Go to https://www.vauxhall.co.uk/owners/maintenance-and-repair/service-exclusions.html to see full Vauxhall Service Club exclusions. Not valid in conjunction with any other offer. Offers apply to genuine Vauxhall service, MOT and repair work on your UK registered Vauxhall at participating Retailers only. Vauxhall Motors Ltd reserves the right to modify the terms of this promotion at Vauxhall’s discretion at any time."

For the issue related to "HeroImgLink" not working; ensure you are using "RedirectTo" ampscript function within your HTML.

<a href="%%=RedirectTo(@HeroImgLink)=%%">