Hello !
Since few days, all pages with a certain template are automatically named “1” in my admin panel.
I don’t know what I’ve done, and I don’t see real differences in my yaml template between the buggy one and others.
Is anyone know where this comes from ?
Probably from the pages’ frontmatter (template.md)
title: 1
Hey thanks for the answer. You mean the .md of the page ? There’s a title entry, and its not “1” : /
Weird then. Does this page template come from some plugin? Did you update plugins recently?
Nope : / It’s a grav fresh install. Only plugin I added was TinyPng, but after turning it off it doesn’t change anything. Plus, the plugin is not supposed to interact with templates.
If it’s a fresh install, I assume it’s one of the default Grav/Quark templates, correct?
No I created a new template with devtools… I feel like I’m missing a really obvious thing… 
I feel like I’m missing a really obvious thing…
So do we, because you’re not sharing much…
To prevent any confusion: One cannot create a “template” with DevTools. Only themes/plugins/blueprints can be created.
When creating a theme, one can choose between ‘pure-blank’, ‘tailwind’, ‘inheritance’ and ‘copy’. A newly created theme may contain some simple “Twig templates” in folder ‘/templates’.
Would you mind sharing which exact steps you have taken starting from a scratch Grav 1.7.18 install allowing use to reproduce the issue?
Sorry ! I’m a bit new to Grav, so i’m not sure what to share. 
At first I though that maybe I was a known issue, but it seems not.
If I remember well, I use devtool and chose the pure-blank theme. I named it the way I wanted, then, I erased all default blueprints and make mine.
Here is the full code of the buggy blueprint :
title: Paragraphe
form:
fields:
tabs:
type: tabs
active: 1
fields:
content:
type: tab
fields:
header.titreParagraphe:
type: text
label: Titre Paragraphe
header.paragraphe:
type: editor
label: Paragraphe
header.centrage:
type: toggle
toggleable: true
label: "Centrer texte"
highlight: 1
default: 0
options:
1: Yes
0: No
validate:
type: bool
header.menu:
type: toggle
toggleable: true
label: "Insérer dans le menu"
highlight: 1
default: 0
options:
1: Yes
0: No
validate:
type: bool
header.titremenu:
type: text
label: Titre Menu
And an image of the structure of the theme “Partisan” I made :
There’s no .html.twig template associate with blueprint because it’s a one-pager and all is happening in the default.html.twig
Here’s is the complete .md of a page that display the “1” title:
---
title: 'Pains et Poncifs'
titreParagraphe: Regard
paragraphe: "Comparer [blablabla cuted text blablabla] subjective."
menu: true
titremenu: Regard
---
What can I share that would also help ?
Thanks everyone for taking time for this issue 
Thing is, those “1” titles did not appeared right in the begining. I think I must have done something after, but it’s hard to trace back exactly all what I did. I’m going to investigate more.
It was. Or I guess. I changed
header.menu:
by
header.appearancemenu:
And the “1” was gone.
But out of curiousity, why did this happened exactly ?
@edi0th, Just an educated guess…
The ‘Pages’ page In Admin lists all pages by their ‘Menu’ name as set in the header of the page like:
---
menu: Typography
---
Blueprint field header.menu defines the menu variable in the frontmatter of the page.
Since your blueprint uses the Grav reserved header.menu for a boolean (using 1 and 0 as values), Grav will happily take that value as the name for the menu. And Admin will happily use that value in its list of pages.