Error with numeric values returned from query.

Mac OS X 10.15.5
Brew installed: python@3.8 and mariadb-connector-c
pip installed mariadb connector version 1.0.0

Python Version:
(Python 3.8.3 (default, Jul 8 2020, 14:27:55)
[Clang 11.0.3 (clang-1103.0.32.62)] on darwin
Type "help", "copyright", "credits" or "license" for more information.)

In DB data looks like:
mysql> SELECT date, time, id, value FROM odczyty WHERE date = '2020-07-16' ORDER BY seq_no DESC LIMIT 10;
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10 rows in set (0.01 sec)

In script
cur.execute("SELECT date, time, id, value FROM odczyty WHERE date=? ORDER BY seq_no DESC LIMIT 10", (today,) )

returns values like:
Date: 2020-07-16 17:55:01 | id: 28-0116231917ee | value: 17.875
Date: 2020-07-16 17:55:01 | id: 28-02161fc3e5ee | value: 17.937000274658203
Date: 2020-07-16 17:55:01 | id: 28-01162336c8ee | value: 17.875
Date: 2020-07-16 17:50:01 | id: 28-0116231917ee | value: 17.875
Date: 2020-07-16 17:50:01 | id: 28-02161fc3e5ee | value: 17.937000274658203
Date: 2020-07-16 17:50:01 | id: 28-01162336c8ee | value: 17.875
Date: 2020-07-16 17:45:01 | id: 28-0116231917ee | value: 17.875
Date: 2020-07-16 17:45:01 | id: 28-02161fc3e5ee | value: 17.937000274658203
Date: 2020-07-16 17:45:01 | id: 28-01162336c8ee | value: 17.875
Date: 2020-07-16 17:40:01 | id: 28-0116231917ee | value: 17.875

but when run like this:
cur.execute("SELECT date, time, id, value FROM odczyty WHERE date='2020-07-16' ORDER BY seq_no DESC LIMIT 10")

returns proper values:
Date: 2020-07-16 17:55:01 | id: 28-0116231917ee | value: 17.875
Date: 2020-07-16 17:55:01 | id: 28-02161fc3e5ee | value: 17.937
Date: 2020-07-16 17:55:01 | id: 28-01162336c8ee | value: 17.875
Date: 2020-07-16 17:50:01 | id: 28-0116231917ee | value: 17.875
Date: 2020-07-16 17:50:01 |t id: 28-02161fc3e5ee | value: 17.937
Date: 2020-07-16 17:50:01 | id: 28-01162336c8ee | value: 17.875
Date: 2020-07-16 17:45:01 | id: 28-0116231917ee | value: 17.875
Date: 2020-07-16 17:45:01 | id: 28-02161fc3e5ee | value: 17.937
Date: 2020-07-16 17:45:01 | id: 28-01162336c8ee | value: 17.875
Date: 2020-07-16 17:40:01 | id: 28-0116231917ee | value: 17.875

Server is MariaDB 10 on Synology.
I've attached DB dump and python test script.