Odoo 12 : Changes are not visible when updating existing module - odoo

Question

I am trying to update some static text in template name ajax_login_template.xml inside website_ajax_login module.
I have restored an existing dump file without any errors.
The issue is that I can't see the changes after updating the app in developer mood.
But the changes get visible as expected when I use a new database instead of the dumped version and fresh install website_ajax_login_module. To simplify my question and what I did as follows:
First Attempt
Step 1 -> Restore dump file into a database.
Step 2 -> Update template.xml file
Step 3 -> Activate Developer Mood and upgrade the App. i.e. `website_ajax_login`
Result ===> Changes Not Visible.
Also if I click on top menu item "Customize -> HTML/CSS editor". No windows open at the right side of the screen.
Second Attempt
Step 1: Go to web database manager view
Step 2: Create a database (not restore list in the first attempt)
Step 3: Install website_ajax_login app
Result ====> Changes Visible I made in the template.xml file.
if I click on top menu item "Customize -> HTML/CSS editor". The window opens on the right side of the screen without any problem.
Is there some cache etc involved in this error. When using the dumped version of my database, I see the error logs as follows.
2020-05-18 10:58:57,541 127210 INFO archixpress odoo.addons.base.models.ir_attachment: _read_file reading /home/shahzeb/.local/share/Odoo/filestore/archixpress/bd/bdbf3e6ea7597eb4b2305c7e8e083430facaa1b2
Traceback (most recent call last):
File "/opt/odoo/odoo/odoo/api.py", line 1039, in get
value = self._data[key][field][record._ids[0]]
KeyError: 38054
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/odoo/odoo/odoo/fields.py", line 976, in __get__
value = record.env.cache.get(record, self)
File "/opt/odoo/odoo/odoo/api.py", line 1041, in get
raise CacheMiss(record, field)
odoo.exceptions.CacheMiss: ('ir.attachment(38054,).datas', None)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/shahzeb/Projects/Wiztech/odoo/odoo/odoo/addons/base/models/ir_attachment.py", line 113, in _file_read
r = base64.b64encode(open(full_path,'rb').read())
FileNotFoundError: [Errno 2] No such file or directory: '/home/shahzeb/.local/share/Odoo/filestore/archixpress/bd/bdbf3e6ea7597eb4b2305c7e8e083430facaa1b2'
2020-05-18 10:58:57,561 127210 INFO archixpress werkzeug: 127.0.0.1 - - [18/May/2020 10:58:57] "GET /web/image/38054/160x160/ HTTP/1.1" 304 - 5 0.009 0.041
2020-05-18 10:58:57,575 127210 INFO archixpress odoo.addons.base.models.ir_attachment: _read_file reading /home/shahzeb/.local/share/Odoo/filestore/archixpress/26/269f4b4e91c4bc57d9d535ad3c8fcd907d975031
Traceback (most recent call last):
File "/opt/odoo/odoo/odoo/api.py", line 1039, in get
value = self._data[key][field][record._ids[0]]
KeyError: 38056
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/odoo/odoo/odoo/fields.py", line 976, in __get__
value = record.env.cache.get(record, self)
File "/opt/odoo/odoo/odoo/api.py", line 1041, in get
raise CacheMiss(record, field)
odoo.exceptions.CacheMiss: ('ir.attachment(38056,).datas', None)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/shahzeb/Projects/Wiztech/odoo/odoo/odoo/addons/base/models/ir_attachment.py", line 113, in _file_read
r = base64.b64encode(open(full_path,'rb').read())
FileNotFoundError: [Errno 2] No such file or directory: '/home/shahzeb/.local/share/Odoo/filestore/archixpress/26/269f4b4e91c4bc57d9d535ad3c8fcd907d975031'
2020-05-18 10:58:57,578 127210 INFO archixpress werkzeug: 127.0.0.1 - - [18/May/2020 10:58:57] "GET /web/image/38056/160x160/ HTTP/1.1" 304 - 5 0.009 0.041
2020-05-18 10:58:58,001 127210 INFO archixpress werkzeug: 127.0.0.1 - - [18/May/2020 10:58:58] "POST /web/dataset/call HTTP/1.1" 200 - 3 0.051 0.032
2020-05-18 10:58:58,079 127210 INFO archixpress werkzeug: 127.0.0.1 - - [18/May/2020 10:58:58] "POST /website/translations HTTP/1.1" 200 - 12 0.116 0.142
2020-05-18 10:58:58,095 127210 INFO archixpress odoo.addons.base.models.ir_attachment: _read_file reading /home/shahzeb/.local/share/Odoo/filestore/archixpress/cd/cd5a21b5fca4934040122813fb0d1214003f6ca7
Traceback (most recent call last):
File "/opt/odoo/odoo/odoo/api.py", line 1039, in get
value = self._data[key][field][record._ids[0]]
KeyError: 38113
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/opt/odoo/odoo/odoo/fields.py", line 976, in __get__
value = record.env.cache.get(record, self)
File "/opt/odoo/odoo/odoo/api.py", line 1041, in get
raise CacheMiss(record, field)
odoo.exceptions.CacheMiss: ('ir.attachment(38113,).datas', None)
During handling of the above exception, another exception occurred:
As a test, I Created a new module and every thing works fine with new module.

Answer 1

Had a similar problem because someone had altered the view using debug tools inside Odoo. The solution can be found on this question: https://stackoverflow.com/a/43650510